Nothing wrong with spawning pet shop Betta-A Betta either meets standards or it doesn't-the only difference with a pet shop Betta is knowing its genetic and often you won't know this with some breeders either-depends on how well they keep records and how willing they are to share.
It also depends on your goals-if you want to show-look for a Betta that meets the IBC standards as close as you can with mate that complements them.
If you just want to see if it is something you would like to learn to do...That is fine too..IMO......You have to start someplace-you can only read and research so much-at some point you have to get your feet wet so to speak. As with most things it can be a trial and error issue-especially with living creatures.
What is important is to be responsible and have a plan.
Lots and lots of different methods to not just keep this species-but to spawn and rear fry successfully.
You can spend a ton of money or very little-you can go high tech or low tech.
When I cupped my males for grow out-I used pint and quart canning jars-but now I am able to keep all the males and females together long term (this was one of my goals)and so I only cup short term to condition for spawning.
Personally I have found that the natural method to work best for me-For others they like the standard method and the standard method is often the best method to try when its your first time spawning this species.
Live foods are best, however, you can still rear fry on processed, cooked egg yolk and frozen foods-Its done everyday by some breeders. Its finding what works for you, what you have on hand...etc......
Not really a right or wrong way to spawn-its finding what works for you and your breeders and this can changes from spawn to spawn-even with the same breeders sometimes too.....They are living creatures after all....lol....
Most important.....have fun...that is what this hobby is all about after all....