As a heavy user of IRC, I would say yes. At least, I wouldn't be able to use it without irssi running inside tmux on some server, and everyone I know does the same.
For a large Free Software project, we use Mattermost (a Slack clone with unlimited history) and it works great. There are a few features missing, but it has been a huge boost for engagement. As someone who has been using IRC for 20 years, I never thought I could get used to using a web-based client, but it's worth it.
Small annoyances, such as having to educate people not to use "@channel" because it will email a notification to 300 people, but it's just a matter of time before it's fixed.
(I don't use Gmail, but a ton of tech people do. Something like Mattermost is rather harmless, since less critical than email.)
For what it's worth, Mattermost also package native desktop applications for Linux, Mac, Windows and iOS/Android. The desktop ones are basically a wrapper around a standalone browser. Has better native desktop notifications integration.
Like I wrote above, I'm not a real IRC user because it doesn't support async messaging well, and I was curious if there was a viable xmpp-like async mode. I love email and xmpp because they works like git in that I can use it offline as well. Please don't argue that everything is 24/7 connected due to IoT or something like that as an explanation why offline mode has no use today.
Async messaging has other advantages, like drafting a response and pondering about the details over one or more days. That said, realtime chat has its place, but with distributed teams it's most practical to use distributed async messaging for the normal case and fall back to realtime protocols when you need a live conversation. I consider live communication to be the same as calling someone on the phone and disrupting their workflow or failing to reach them due to being unavailable at the moment.
Don't get me wrong, IRC and monitoring chat rooms works for many developers, but that doesn't mean it must work for me as well. We're not all the same after all. When I use live comms, it's on-demand, like a phone call.
I'm also a heavy mutt and irssi user. I think their UI stability is more an issue on how application authors deal with change/improvements, but I agree there's probably a technical factor where libncurses offers less flexibility than HTML/CSS does, so web apps are much more likely to change often.