Definitely a needed sort of product; my congratulations to the team.
A non-Slack alternative: I was looking for this feature, but wanted to move my company away from Slack to one of the free chat platforms like Rocket.Chat, Mattermost, Zulip, etc. So I researched, and found that only Rocket.Chat has its own version of this live-chat feature (though no doubt much less mature). I'm looking forward to switching over to Rocket.Chat soon (I have no affiliation with them).
https://github.com/RocketChat/Rocket.Chat/issues/519
Hope this helps folks out there looking for live-chat integration options. It's pretty cool to be able to chat with potential users directly from company chat!