I am certified for 18 years and it was a good move for me.
The information,monthly magazine,conferences, videos made available
Insurance was cheaper
Makes getting jobs easier
I was able to get free tennis working vacations in Caribbean
cost money to get certified, and each level up, yearly dues
You are 100% correct about certain certified teachers. Many didn't play at a high level and went the academic route thus explaining their elitist attitude and lack of real life teaching skills.