>>5476904It's not a stupid question, don't worry.
The quick answer is: primer is preferable in this instance and it's what most people would recommend.
The long answer is: Primer is a bit different from standard acrylic paint. Standard acrylics are meant (typically) to be thinned so that the application of them runs smoother; primer is meant to have an ever so slightly rougher consistency, because it is meant for enhancing the ability of the paint to adhere to the surface while it cures.
As a metaphor, the raw plastic of your figure could be imagined as a laminate tile floor. If you drop paint on it, the surface adhesion won't be absolute. You can clean it up. Now imagine primer as a carpeted floor. Same paint mess is dropped on it, and man alive is that fucker gonna soak up every last drop.
So you CAN use white acrylic, but you're going to have to glob that shit on and it won't look very nice at all. We're talking pooling, streaks, brush marks, inconsistent coverage... all the bad shit that makes so many newbie customs look awful.
A primer on the other hand will go on in 1-2 misted applications, level out, and not reduce details or alter the surface in any discernible way. You might need to wet sand the primed areas slightly, but that's mostly going to come down to how dry your environment's air is, the temperature, and a million other factors.
