I agree with some of the author's concerns in his blogpost. But the real context of his post is here: https://twitter.com/airmailer/status/1150562754534748161

To me, this sounds like a desparate reason to try to captialise on moving to a subscription-based plan. In-app subscription for email push notifications with multiple account support? I'm not convinced.

I'd rather use/migrate back to the stock email app than subscribe to something like this.