I am not convinced that is better. Firstly important security fixes will be pushed as hotfixes past nightly into main instead of waiting for a regular patch cycle. Otherwise you are just announcing bugs to the world.

Secondly there is a reason why nightly channel exists. It is because it is not stable. Yeah, back in the day I ran nightly for years without seeing an issue, but also I'm not really sure if there was any benefits.

As far as I am aware the dev channel is just main Firefox with better webdev console/tools. So I don't know if that has anything going for it security wise compared to the main.