They’re no better or worse than standard HT BBs, in my experience. And fitting/removing them isn’t that much hassle.
I don’t see the issue. Nobody complains about press-fit headsets.
The press-fit BB on my Stumpjumper FSR doesn’t seem great to be honest. After a wet ride, it tends to get really stiff & need riding for a while to loosen off. I don’t even get to ride the bike that often, so hope it will last a long time, but am not expecting it to.
Fitting/removing them doesn’t seem too difficult, but the proper tools to do it seem quite a lot more expensive than something like a HTII tool.
Press-fit headsets are a bit different. You press the cup in & that’s it. The Cane Creek S3 on my Inbred has standard bearings that are easily replaced. The cups don’t need to come out. I suspect I will still be using them in the same frame for years to come.
And headsets as already mentioned, aren’t in the firing line of all the muddy water & crud that gets thrown up down by the BB.
Isn’t the BB91-42a a specific Specialized thing?