I've been playing chess online with one of my sons, and with a young fellow in India, via Chess.com. The games we've been playing have been spread out over days, because I'm not always ready to commit to spending a half an hour playing someone in real time. I've done this once or twice and find the pressure rather high!
But the long slow games, rather like the old correspondence chess, which my father used to play in his heyday, are difficult to keep track of, for me. I don't have the greatest of chess brains, and can't come back to a board and remember how I got to where I am and what I planned to do next. Chess.com allows you to play back through your moves, which is helpful, but I still make more mistakes than I would in a face-to-face game. (Although my face-to-face games seem to have got worse since I started playing online.)
I need the concentrated focus that comes with a game where you're playing a real live opponent and can see what they're doing with their body language. That shouldn't make a difference, but it does. I guess it's a bit like poker, where you're trying to read what's going on in the mind why the way the other player's body moves.
Years ago I used to be involved in a chess club here in Dunedin, but only in their round robin games that various four-men groups would play around the city. This part of the club was called Chess for Fun. I had one opponent who could spend long minutes at a time sweating over the right move, breathing heavily, and oblivious to the rest of the world. It wasn't fun to play with someone going so slow, but on the other hand I did win one or two games against him, as I recall. Much to my surprise and his, since he was a much more experienced player.