I think that perhaps we are working with different definitions of "Paper Tech"
If we are taking about a fully participating "Paper Tech", where the director, all the designers and stage managers sit down and go beat by beat through the show - I think this could be very helpful on a very complicated show, but if the show is huge, you might have a hard time pinning down everyone for the amount of time needed to make this meeting useful.
If you are talking about a department by department "Paper Tech", where stage management meets with each designer independently to get cues from them and book them, I still see some use in this, and you may have more of a fighting chance in making this happen. (But again, you may have trouble pinning them down.)
There is also the paper tech that stage management can do on their own - which is basically doing the run sheets ahead of time. Where you take everything you know based on rehearsal and lay out, to the best of your knowledge, based on what you have learned in rehearsal, and document your "Game Boarding" on the show.
I have to say at the level I work at, unless the director requested it, I would never push for a paper tech - it's not something that is typically done (and often, in the US, smacks of Educational Theater - which is negative stereotype for something that would be immensely useful for stage management.) I just don't have the time that final week when everyone is in town to sit down for a couple of hours (And very few producers want to pay the SM overtime that would be required.)
I often find that paper techs turn into design conversations and a lot of time is wasted.
The way I work with my team, is from pre-production, we starting working on the run sheets, automation sheets, quick change plots, sound cue lists, and update them daily as learn the show (for example, if in the rehearsal room, we want a scene change to take 20 seconds, then we start looking at the automation sheets how it can happen in that time.) So, we start our tech process from the first day we on are contract.