What I have heard is that acrylics benefit from a primer to improve adhesion. Plus you get a preview of your seam work. What some people do is use a lacquer or enamel primer, because they "bite" the plastic surface better.
I always prime my kits, to check for flaws and to make sure everything is completely opaque.
I had some crazy chipping and even some "welding" between robot parts that were painted with acrylics. The paint on the shoulder armor of a Gunpla kit kept sticking to the body, resulting in scabs of paint stuck on both parts. I repainted 3X, and the same thing happened. This, plus the chipping at moveable parts, put me off using acrylics for poseable models.
But for something that doesn't move like your YF-19, acrylics are fine. I do find they seem to spray to a smoother finish than enamels.