Having done both, the in-person and the file sharing, the in-person is radically better... for me at least. I get that real-time synergy that happens when jamming that just can't be replicated by file sharing. But, I get that's what works for me and I'm totally ok if that doesn't work for someone else.
I think what makes a great song is that synergy, taking something that's good and turning into something amazing because different people are working it at the same time. So much music these days is so sterile feeling, which I've come to believe has a lot to do with the influence of virtual tech. I mean, rock/metal bands that cancel gigs cause a laptop got stolen? No thanks. Playing to click tracks, or worse basically karaokeing your own music? Also, hard pass.
As to the play my own stuff versus someone elses, I want the influence of others on what I'm writing. I want "my" music to become "our" music. But, based solely on past experiences, playing well is a different skillset than writing well and while I've found dozens and dozens of guys to jam with over the years who played well, the guys who wrote well I can count on less than 2 hands. Not to say I'm some amazing composer, but I know how to write what I want to play and people seem to dig it... in the end, though, again, hoping that "my" turns into "ours" to get that synergy that takes a song places no one single person can get them to go.