True, it is probably too early to offer bitcoin payment solution straight away, because not everyone will be able to handle it well without prior deeper knowledge of bitcoin. ~
I don't think a tea salesman needs a deep study of Bitcoin to work with him. Everything comes with experience. For starters, he can install the Samurai app on his smartphone. There he will get his first SegWit address and will be able to accept bitcoins. After a while, when he gains experience and knowledge, he will be able to run Lightning Network Node.
P.S. The most important thing is to interest the tea salesman in Bitcoin.