Pretty sure you can talk to friends while in game, i think i did it a few times. There isn’t exactly much free time there so wouldn’t complain even if that was impossible.
On a general note, i don’t understand what a general chat is good for besides spamm. If you want to talk, you have friends list for it, and forums as well. If there were guilds or something like that, guild chat could be interesting, maybe, don’t know.
If they ever add a global chat i feel like it should be optional.