So its not really a requirement that I have to obtain a work permit or can I simply work in Thailand on my business visa?
The You cannot work legally in Thailand without a work permit. And a non immigrant “B” visa is required and should be obtained first to apply for a work permit. It is illegal to work in Thailand with out a valid visa and work permit.
There is a common misconception that the “B” visa allows you to work in Thailand. This is incorrect as stated as it only allows you to apply for a work permit while in Thailand. The “Business” visa is not a work visa as there is no such visa which allows you to work in Thailand.