It's a little annoying if someone buys in short when there are guys on the list that will be in for 10-20k yeah definitely. Plus being a tight player doesn't really payoff at higher stakes. People know youre tight and therefore you don't get called. Even if I get called bluffing with air I always show it to let the table know I can have anything in those big spots. It helps me get called off when I have to goods.
The biggest difference between those two stake levels is the caliber of players playing in the game. There more 3 and 4 betting, more bluffing, a lot more advanced level play in general. When you are able to play super deep then you can open your range a bit because you have more money to play with and you can pot control a lot better. Buying in short limits you to having to play tight and basically shove. It eliminates all your bluffs and you generally don't get full value or called off from opponents. My rule of thumb when going to bigger stakes is to buy in short but not necessarily for the minimum.
And to your second point yes there is a much wider array of skills required to play a bigger range of hands. In 2-5 if youre raising from late position you're in control of the hand most of the time. That's not the case in 10-20. Players will 3 barrel bluff or overbet the pot and make weird plays just to throw you off. Again the skill set required to play 8s or better isn't that difficult. Everyone knows when to trap or how to try and build a pot. The skills in 10-20 can include things like c-betting suited connectors in a completely wiffed wet board and just barreling off trying to get a better hand to fold. Betting on a 4 to the straight board or even shoving the river after a big bet just to apply pressure. Its just much more varied play and therefore you need to learn how to adjust and adapt your game without being too predictable.