I'd been doing that somewhat too, but also a mix of the old -ProfileManager. The new UI is shiny enough I may consider consolidating to just one Edition, though I haven't decided which Edition yet.
(Fun fact, you can even switch to the Developer Edition default profile from regular Firefox with the -ProfileManager though that is not generally a good idea because Developer Edition is intentionally a half-step version or two ahead of "retail" Firefox. Developer Edition assumes you don't mind being a little bit closer to the bleeding edge. Still not the same as using Firefox Nightly as your daily driver, but still often a "power user preview" version.)
(Fun fact, you can even switch to the Developer Edition default profile from regular Firefox with the -ProfileManager though that is not generally a good idea because Developer Edition is intentionally a half-step version or two ahead of "retail" Firefox. Developer Edition assumes you don't mind being a little bit closer to the bleeding edge. Still not the same as using Firefox Nightly as your daily driver, but still often a "power user preview" version.)