Fwiw this has been my setup for ~10 years now and I don't really see an issue with it. Screen locker crashing would have been a concern back in the Xorg days but I don't think it's an issue nowadays with the ext-session-lock-v1 Wayland protocol. I value startup speed and simplicity of my setup and have no use for features provided by a DM, so this has always felt like a no-brainer to me.