IMHOm what is nice (ie what you want out) of mid-deeps is its shortest socket height that will cover almost any fastener with 5-10 exposed threads.
Designers are supposed to spec 1-3 exposed threads, with 5 thread "design" max and 10 thread absolute tolerance spec. So if your mid-deep covers that 5-10 thread range, it will typically fit any "normal" application, meaning you can keep your 50mm deeps assigned to special-use cases only.
Calculate your bolt-depth clearance accordingly. You definitely don't need a 50mm tall socket to do 10 exposed threads, but I'm skeptical 30mm is tall enough. I'd go 32 for the extra lee-way and higher percentage of positive fits vs havin uncertainty the mid-deep will fit.
But that's just personal experience/opinion, maybe somebody else thinks differently.