Why do jews have such big noses??? Because air is free!!
Jew jokes aside, I've personally made the following substitution in my mind for data vendors:
Professional= non-personal use, non-pro = personal use.
So a broker using data to advise clients, yes, pay up. Prop trader required to have a S7, pro fees are a rip off.
I fall into the second category. I also subscribe to the same exchanges from up to three different data vendors. I'd actually be happy and willing to pay pro fees once per exchange, but each data vendor requires you to pay. So I've taken the stance that the data is for my personal non-professional use. My firm makes me pay pro fees for exchanges through my trading platform, I do not pay pro for the ones I sign up for on my own.
My opinion does not agree w/ the exchange agreements and standard definition of pro, so as usual this advice is worth what you paid for it.