So you have been riding for a while, and except for a few pointers here and there, you have pretty much taught yourself.
That is pretty impressive.
So is there any point to ever getting snowboard lessons? Here are some reasons for getting some extra help on the slopes:

1. Eliminating any bad habits.
   You cannot see yourself snowboarding.
   Having someone watch you and point out any bad habits can be very useful.
   
2. Reaching your goals faster.
   Perhaps you would like more confidence and control on double blacks, or more air in the terrain park.
   Even a 1 hour lesson can give you some new information and set you on your way to achieving these goals faster.
   
3. Learning different techniques.
   You may be quite confident and in control on most terrain and still you may not know everything about snowboarding.
   Sometimes, even a small suggestion about a new way to turn can make a huge difference.
   
4. Seeing more of the park If you are new to the area, an instructor may be able to take you off the beaten path and show you the best that the resort has to offer.
   
5. Challenging yourself in the safest possible way.
   You may have said to yourself: "tomorrow I will try both frontside and backside 360s for the first time".
   Sometimes, it can be easy to focus on doing the jump and forgetting about your safety.
   Having an instructor with you will ensure you achieve your goals in the safest possible way.
   

It is true, you should ride only for your own satisfaction and enjoyment.
But if you are committed to improving, advanced snowboarding lessons will make a huge difference.