Slack is worse. If you don't pay, not only do they not give you access to >10k messages, but they still store those messages and don't allow you to do things like delete them.
I never really thought about it before, but the non-deletion might offer Sarbanes-Oxley protection which could lead to publicly traded companies being more tolerant of teams using slack without clearing it through central IT.
It doesn't. Big companies who want to be gdpr compliant buy enterprise Slack and force slack to store the data in European datacenters. Slack doesn't give a shit about gdpr if you're not paying
Depends: Do they not delete the data if you explicitly contact them and tell them to do it, or do they just not give you a convenient button in the UI?
I do feel that the data residency law should be respected regardless of whether a customer is paying or not. Otherwise it's like a restaurant offering not to spit on your food if you paid for the premium service...