For many years I painted and rarely primed the surface, I only used primers for a coat that would allow me to sand it for a smooth surface under paint. I didn't often have lifting problems while pulling masking tape, maybe because I always carefully washed and rinsed the plastic before assembly, with a thorough wipe with clean cloth and alcohol before painting.
Now I find a good primer coat gives me a hard and durable surface, that sands easily before paint by just using a 1200 grit polishing pad. It also gives me a surface that clearly shows any faults in my preparation of the plastic joints, or filled repairs. Much better and easier for me to make any needed corrections, prior to the finish coats being sprayed on.
I had good results from some of the commercial spray can primers that were sandable, but they seem rather inconsistent now, as I think they may make frequent formula changes that alter the results.
For some time I have mostly been using Badger's "Stynylrez" primer for acrylic paints, and Alclad's primer for painting with their lacquer metallic finishes. Either gives me very good results, and I have had zero lifting or final finishing flaws using them routinely.
But there is no absolute rule that says you can't get a fine finish without using a primer, Plastic Junkie and others turn out some perfectly beautiful work without priming. As always it's an individual choice, by trying it both ways, prime coat or not, you'll determine which is right for you.