Too broad a question to really answer, really it depends on the content. If it's good, then good! Power to ya. If not then well, its a waste because we can easily access all the same info and know all the same stuff, if you're not enjoyable then its just watching you go around talking parks and thats no good to anyone. I will say, IDK how large the YT theme park community even is! Its generally something I avoid. Most of it doesnt do much for me, like I said alot of it isnt interesting to me, and deff can come off as self aggrandizing, look at me look at me!
I just enjoy discussion more than hearing what someone else has to say about parks and rides.
That said I am a fan of coaster studios. At first I found him a tad annoying and thought it was just look at me, but I watched more (guess that says something) and I really like him now. Seems like a sincere, down to earth guy that actually isnt doing it for attention and has a real passion for it. Also at first I stumbled on his parodies, some were funny some were not, but I saw his park and coaster reviews and they're really good. He doesn't seem as OTT and crazed as some enthusiasts either, more realistic.
And true defunctland is pretty cool.
Guess like anything it just depends on the content.
I have numerous times before thought about a park blog and possible YT channel, but I never had the energy and feel like it could be a lot of effort and I'd like pay off, and realistically its not gunna get any traction. To my above point, I have nothing new or interesting to say and am not sure why anyone would care about my rankings or thoughts and I cant break news any faster than the sources I get em from so oh well lol