I'd imagine that question is how much does management care about whatever interpretation or use they have for the setting for Tempus' Hololore. Vesper has shown time and time again that he very much never wants to get into trouble or bother his boss with anything unless he has to. He doesn't overload management with perms requests, he got panicky due to DMCA bullshit with Spore to the point that he felt like ending the stream early, and overall he has shown that he tries not to be a nuisance so he doesn't get in trouble or bother people.
Because anything Vesper says about "Elysium" could be considered canon once you turn it from an inside joke of calling Australia "Northern Elysium" to Northern Elysium actually having geography, lore, economy, culture, political bodies, and all that sort of basic worldbuilding elements you'd expect to be shown in a fleshed out TTRPG. Vesper is an autistic perfectionist while being a long time DM. If I were in his position I'd have already written out a first draft for all four corners of Elysium if management let me. It is just a bunch of potential management bullshit that someone like Vesper probably would want to avoid. Oh and having to avoid potentially using the Tempus boys as NPCs if the story justifies it, as that can be kind of weird too depending on how much you care about plot in a TTRPG.
Calli's campaign to my knowledge had nothing to do with anything Holo related, it was purely a custom scenario that has nothing to do with HoloMyth. If Vesper ran HoloElysium as the setting, then it does become Holo related.
I think Vesper just wants to avoid the problem I've seen with a lot of modern post 5e/Critikal Role DnD where the DM is effectively a waiter for his players and the players are almost spoiled children in what they expect from the campaign. The always expecting a win types, the types who want to just have things go there way as long as they aren't a murder hobo, the type who can go "Hey can I get/use/be X" and the DM is expected to say "Yes" at every point otherwise they are "stifling" them. The type that overly values "fun" over "engagement". I think conflict, restriction, and harshness leads to people who are willing to roll with the punches to a better more engaging game because if you can just do whatever you want then it is hard to be engaged for very long. Their is a real limit to how much fun "just having fun" is IME when it comes to stuff like this. I remember a really old time DM made a huge essay post explaining this concept, and he effectively said that being an overly kind DM with your players is like eating junk food, it is nice for a moment but it is really unfulfilling.
My current problem with Vesper from how he's explained his TTRPG experiences so far is he I think over reached with trying to explain what a "Munchkin" is to someone like Magni who has no clue about this stuff. A Munchkin is an incredibly specific type of power gaming player as they're the type who tries to play full exploit Coffeelock unironically, and then Magni attributed it to stupid shit like "Anyone who plays Half Elf is a munchkin because they have good racial stats and Darkvision." I find these types of DMs who throw around the term "Munchkin" focus far too much on power in a player's build and will wag their finger if you dare make a strong build by trying to cuck you out somehow because you being good at something is "hogging spotlight" when you quite literally made your character to be good at that thing on purpose. Like you should be ashamed that you made your archer Fighter actually really good at shooting a bow for some reason. These types of DMs also tend to reeeeally hate Fighters for some reason due to how on the surface exploitable you can make a Fighter in 5e.
