"Would be valuable to learn that he dresses like a clown or like indiana jones in conferences and my preference on learning TLA?" Of course not. That question is too simple, and you know it! ;)

Could you also ask a question that completely gives a counter example? Could you think of a question that does help learning TLA+ because you know something about Leslie Lamport? Have it as a fun exercise for 10 minutes, or not, it might stretch your mind a bit since you claim that you can't see the relevance.

Here is why I like to know about authors who found a field:

Knowing the author may give an idea or context about TLA+. While not strictly necessary, it may be interesting background information that people don't know about. I presume that Lamport has one of the most, if not the most authentic reason for why he created TLA+ in the first place. Reading that reason may motivate people more to learn more about TLA+, or demotivate people more -- but for the right reasons!

Furthermore, discussions can be associative: gabuzome gave book recommendations written by Lamport. I didn't know Lamport wrote one (I know very little about Lamport) and since he now recommended it I'm happy to know that the founder of TLA+ also writes books worthy enough of a recommendation. It personally gives me more confidence to read it and take a crack at it.