Is Fortnite fun or feud-fodder?

My 12 year old son has been playing this free online game for a month or so now. As with all other fads, we assume it's self-limiting - just like collecting Match Attax or Pokemon cards, playing Pokemon, playing Fifa, buying Fifa points, playing Futdraft on his phone... the list goes on and each fad is replaced by a new one. What will replace Fortnite? Lighter evenings and playing out I hope!

I alternately feel guilty and not so guilty letting him play. Here's my list of pros and cons.

Pros

• Winter evenings. I'm holding out for lighter evenings so he can get back out on his bike again. In the meantime, this stops the "I'm bored" routine - nothing wrong with that from time to time!

• Only child. I can't arrange "play dates" all the time, and the way he plays in a party with three of his mates is almost like having them round to play, but without the waiting on them with snacks and drinks. I do laugh when I hear him giggling, or shrieking with joy as he's won something. 

• No endless Simpsons on TV. Bliss.

• I'd have done the same. Well maybe his dad, not me. I spent hours reading, listening to music, applying makeup, washing off makeup, watching MTV, on the phone to my friends with my dad saying "You've been with Suzi all day at school, what do you need to talk about all evening?" Like he understood...

• Rules and flexibility. After a couple of weeks, we set up rules that if he moaned, he would have his controllers taken away (we have done this) or he would be banned for a specified time if he had a detention at school (not necessary yet!). This has eliminated much of the moaning to stop playing. It also helps if you give warnings, like dinner in 10 mins, or finish this game. You can't pause an online game. My son also says that his mates will choose someone else to play if he leaves mid-game, so he may miss out later. I know that sounds petty but I don't want to cause problems for him if I can just be a bit flexible. It goes both ways...

• I look cool at school. When I'm working in Year 5 or 6, I can talk to the kids about these games like I'm down with them. They think I'm cool even if my son doesn't! (Oh did I tell you I teach coding?!)

Cons

• Time thief. 

1. Take tonight; he's on it as soon as he gets into the house, well after ablutions, and forced jobs (emptying the dishwasher, closing the guinea pig hutch up). He came down on time for dinner, talked about school, then went back up to play. He will probably now play for another hour or so before we "force" him to come down and do something together as a family. 
2. I don't feel too worried about the time though, because he plays 1-2 hours of sport after school most evenings, and this is before he plays out. The downtime is fun time for him.
3. I also find it hard to come down too much on him as I'm on my tablet or phone for the majority of the evening - I'm reading news articles, you know! 
4. We have dragged him out for 3-5 mile walks each weekend recently, which he moans about but does enjoy once he finds something to lob into the sea or something to smash! Last Saturday, we had a 6 mile snow walk with a long pub lunch (4 hours in total). This was after a breakfast out too, so I was happy for him to play for a while when we got home, before watching a film together (Kevin and Perry Go Large - hilarious to watch with him!). When we work out how much time he spends with us being active or doing family stuff, it all evens out. 
5. All holiday time is spent playing board games and being outside. 
6. We've also applied the pressure at school for him as we had a disappointing report at Christmas; the reward for this is for us to be a little less strict with him on gaming time. We are extremely happy that he has made such an improvement at school.

• Attitude. Sometimes he gets annoyed at his XBox or the wifi connection. He gets so upset he wants to throw the console out of the window. Or he gets annoyed by his mates who are not protecting him from snipers (or some rubbish, I don't pay that much attention).

• Cold dinners. We had a few of these issues, but now I go up and set a timer on his phone for 10-15 minutes. He's usually on time.

• Getting ready for going out. We have had many rows about this. We try to give more warnings as although he's 12, he has no concept of time passing. 

• Eyesight. He wears glasses for close work. Heaven forbid we remind him when his mates might hear online!

• Grunting. He will grunt to me when I'm asking him questions. But sometimes he will blow me a kiss.

• Late nights. He had a sleepover for his birthday with one friend. They were SO quiet, I didn't realise they had literally played all night.

• Negative violent connotations. I don't worry about this that much actually. I have read research into the correlation between violent video games and real life violence (google it). I grew up when androgynous pop stars were going to ruin the world (Boy George etc) and for my parents it was the evil rock'n'roll. Nothing changes.

• No wind down time. I try to get him off gaming for an hour before sleep time, but this is the most popular time to play and I don't want him to miss out with his friends. I think coming downstairs to watch TV with us is a good wind down.