The only reason you'd need an oscilloscope in a typical studio...and it's a BIG one...is to check stereo phasing on your mixdowns. This becomes VERY critical if you're doing dance stuff, bass-heavy tracks, as you don't want panning and especially not out of phase signals in the frequency range below 120 Hz if the track in question is destined for vinyl.
Now, the other sort of display I'd recommend isn't a scope...but an RTA. Real-time Analyzers let you see the levels across the entire sound spectrum, and they can come in handy when trying to chase down hard-to-kill frequency "lumps" that're jumping out of the mix. And if you don't have a reliable set of monitors (and why wouldn't you? your monitor chain is probably THE MOST CRITICAL DEVICE in the studio), you can use the RTA to try and fix the discrepancies in the mix that your monitors are causing. But as far as that's concerned, I reiterate...they're the most critical part, and THEY should be fixed if you know you've got issues, tbh.