Although the new CEO has only been in place for about a week. I bet this acquisition has been in the works for longer than that.
[1] https://techcrunch.com/2021/02/23/the-new-new-slack-quill/
This seems like just the result of unfamiliarity with the payments domain to me, rather than "horrible" branding.
I’ve heard someone mix up Slack and Stripe. Doesn’t mean those two are bad branding. The person isn’t someone who cares about SV or startups.