It makes sense to me. How does the mix sound pre-processing, verses post processing.
While it's always nice to A/B...the problem or consideration with this approach is that FX/Processing for a mix tends to be a journey in stages. You don't ever go from no FX/Processing to all you FX/Processing in one pass.
So...as you add a little of this or that...you can A/B back with the previous "version"...but to add a bunch of FX/Processing over time, and than drop it all out and go back to nothing...mmmm...hey, if it helps, do it...but I don't know how helpful it would be...?
I mean...you build a mix...it's not just one layer of FX/processing....and when you add/change something, you get acclimated to that sound...and THAT is your new reference, and then you move on.
Not to mention, there is a lot of "spot" FX/processing that can happen in a DAW, so it's really not easy to remove all of that and get back to your raw, original tracks with a click of a button.
The best option would be to just save a "raw" file version before you start...but again, to use an analogy...if you build a house, and you slowly add things, change things, and you watch it evolve...who cares about seeing it again at the foundation level?
That said...I do agree that if you find yourself struggling, and/or hearing a mix run away on you into something you don't like...then yeah, by all means, stop and strip all that shit out, and start at the beginning.
In the end...use what works for you, nothing really wrong with any approach if it gets you where you want to go.