Not thrilled with yet another subscription. I get it though, as they have to maintain their app with Google's moving Gmail API.
I understand paying for this if you're a paying Google Workspace customer. But if you're a free gmail user, it doesn't make sense. If you're going to pay for email, pay for the actual email before paying for a client.
But most Google Workspace customers are companies, not individuals. It'd be hard to convince the company to pay for Mimestream, so its customers are people. And there are too many "personal productivity" tools competing for my money, Mimestream is very low on the priorities list.
I understand paying for this if you're a paying Google Workspace customer. But if you're a free gmail user, it doesn't make sense. If you're going to pay for email, pay for the actual email before paying for a client.