I had the same thought, but made the opposite conclusion. I setup gmail and outlook to work like hey and tried them for a week each. While it technically worked

I had the same thought, but made the opposite conclusion. I setup gmail and outlook to work like hey and tried them for a week each. While it technically worked, their UIs are not optimized for that type of work flow so it was a lot more clicks to achieve the same ends. After my experiment I paid for Hey, and have been really happy with it.