A blade grinder chops. You may have one capable of chopping the coffee pretty fine, but you still have little chopped pieces.
A burr grinder grinds. When I set mine on the finest setting, the coffee comes out almost powder like.
My burr grinder is old and middle of the road. Many would probably tell me I should go out and drop a few hundred on a super duper muy expensive burr grinder. But like you, I'm in a happy place. For my needs and tastes, what I have is fine.
It just depends on how fine and consistent you feel you need to go. If you're happy with your blade grinder, I wouldn't let others convince you to be unhappy.
