List hygiene is important but from what I’ve seen most companies have their own way of handling it (or not handling it in many cases). For most orgs the platform defaults are good enough. What’s most important from my perspective is deactivation and also identifying when customers/contacts switch either to a different channel or create new accounts with new contact info. That said there are already a handful of list hygiene tools in the space. But if your tool is compelling and you can figure out where to position it then sure it’s worth a shot.