If it is that old, there is no scraping; you gut the place. Safety protocols in place.
These days, the popcorn is little balls of pearlite or something.
The reason the popcorn ceiling was conceptualized was for acoustics. Ever been in an old house with high ceilings? Reverb. Popcorn was supposed subdue reverb and echo. It does, but only until it gets painted. Then its worthless.