Yeah. I also see now from other blog posts on their account that they like project management and note taking style apps, which, like an email client, would much more reasonably be used daily.

Those apps aren’t only daily use but have a high switching cost. So it’s a double whammy: a company that can get punters to switch into their app at a high rate (despite the cost) must be doing something right and will also have the benefit of a drag on people switching out.