Surprise Tom out of nowhere!
You guys should choose what you want to do for the guild as the group who uses it the most and raids etc. but I would throw in a little £0.02:
I don't tend to get around to chatting to most people here as much as I'd like as I'm not really playing WoW and so on (which is my fault and not anyone else's).
I do however have discord open all the time on my PC and have it installed on my phone, I hang out on a few discords for different reasons.
While I can't promise I'd be on to hang out all the time, the chances of me hopping in to text chat and maybe from there hanging out with people for random chat is probably increased if the groups chat is just a click away. While I could drop in to teamspeak whenever and chat its something I have to specifically open and decide to do rather than just clicking through the servers and spotting active chat.
I know (and have read) some of the concerns, and you should absolutely weigh this less than people who are more actively taking part in guild stuff, but I figured it couldn't hurt too much to say.