Agree, it’s a non-issue really. The third GK is always going to be with the squad home or away so it’s just practical really that if you have an extra space just to stick them on the bench rather than potentially waste a youngster’s weekend.Yh. Ppl seem to forget it's only a few years ago we had 5 on the bench and 3 subs, then 7/3. Most of them won't get on, and the only one that is most irreplaceable if you end up with 2 injuries etc in the same position is GK, so I really don't mind it/see why ppl get such a bee in their bonnet about it. Also taking an extra youth player for the experience may often also mean them missing their own game, so debatable which is the more benficial there. Disgaree sure, but to see it constanly being brought up smacks of ppl just wanting to complain about something imo.
You also need your third goalie to be still focused and engaged and I guess having them on the bench rather than twiddling their thumbs helps with that. Because while 99.99% of the time you don’t need your third GK when you do need them you REALLY need them.