You've both missed the point. I don't actually want to use a PIN diode for anything, it's not something I'm interested in using (well, until I am).
I have an effective system for retrieval (heat and scrape) sorting (mini magnetised triangle trays on a white piece of steel sheet and a small whiteboard marker) storage (labelled small centrifuge tubes grouped in labelled bags, all in lidded container) and identification (bootleg copy of the Turuta SMD codebook + BangGood Hiland component tester + homemade test jig) and retrieval (a spreadsheet which contains lines copied from the codebook of all the possible devices for any one top mark that I actually have). So if I want a particular type of component, I can look at my stock, retrieve R's and C's directly, semiconductors I can just look up the type of device I want in the spreadsheet and test the matching devices to make sure they are actually as expected. Around 95% of devices are identifiable with 95% accuracy.
But diodes are a bit harder because for any top mark there is a greater diversity of candidates for any device. I can still pin it down to one exact diode but it takes more work, and if my requirement is so specific it actually matters then I would just buy it anyway. But usually I want "any switching diode" or "any rectifier over x amps and y volts" or "any schottky diode" or "any zener of x volts", so it doesn't matter, any purchase would be cost based so why pay when my own time is free and I usually get what I want much quicker?
So going back to PIN diodes, the point is, I see a lot of candidates for any diode top mark which include varicap and PIN types. 99% of what I have is ordinary diodes, but supposing I do have an odd PIN diode in there? My curiosity is piqued, what traits do I look for?