It's nice when you use epoxy like Devcon as a sealer. The paint ends up looking so smooth. Those are the lures people are shocked to believe that it is made of wood. I have not had that with poly or just hardener. I've tried a bit of everything in this process. If it is a test bait just for me, I will just hit it with some poly, so I can water test it. Then primer and paint, then epoxy. If it is a bait I want to look amazing, or for a customer, I will seal the wood with hardener, then epoxy to get that glass smooth surface. Prime. Paint. Epoxy (x2 or 3). These are musky baits, so it may be different for smaller bass type lures.
Either way, try it out different ways, see what works well for you.