I worked for a small startup that abused the enterprise program in the same way. Originally it was to get around the tiny (at the time) number of beta testers allowed which then was only 100 unique devices. They did this at my suggestion- we needed a lot of testers but we were capped. Over time the CEO started sending out enterprise builds to all sorts of randoms such as potential investors, journalists, family and friends. I warned the CEO that this technically was not allowed, but I could not find a single instance where anyone had been caught violating the program. CEO brushed me off and continued breaking the rules, even after Test Flight was acquired by Apple and the tester cap increased. The enterprise builds were simply way more convenient.

I have since left the startup, but as far as I’m aware they are still continuing with this practice.