It’s easy to think that climbing that you find simple is indistinguishable in difficulty- I certainly used to but when I had to start again from scratch I was amazed that I could clearly differentiate between the challenge of a Diff, Hard Diff, VDiff etc. Quite an eye-opener.
Having said that, I think there are many reasons why wider difficulty bands (ideally ones that aren’t rock climbing grades) make sense for indoor climbing at all difficulty levels, particularly in the case of massive bunches of problems. They’re just temporary after all.