I’m not an investor at all, but figured I’d still answer your questions from a collectors perspective. 
I’m a collector and never cared much for any investments in general, whether it’s stocks, crypto, or alternative retirement fund options.
Absolutely. It honestly would make my collecting journey a lot easier. Everything is so expensive these days, and Pokémon is releasing more and more over the years in addition to it, so it’s hard to keep up with new releases at times.
100% collector
‘Welcomed’, not really. ‘Tolerated’, would be a more appropriate term. It’s just a part of the ‘Pokémon community’ these days, I guess. Just one of the many facets of Pokémon. 
Hard to answer from a collectors perspective that’s not too well-versed of the investors part of Pokémon, apart from some bits and pieces. 
If I have to name one, it’s likely that there aren’t just two sides to this: collectors vs investors. There is actually a middle-ground as well, of people that are both collectors and investors. Heck, loads of collectors who’ve been in the hobby for decades, like Smpratte, TCA Gaming, Gary “Pokémon King”, GemMintPokémon, etc. are partially collectors and partially investors. By collecting over the years, they’ve gained a lot of knowledge, and used that to buy multiple of a lot of stuff for investment purposes to re-sell one day, which is why they’ve been so successful over the years.
Still, all of those simply grew from their love of the hobby into a side-business to make money while doing it. Which is also why they’ve made it this far in the first place.
There are dozens of investors these days, simply because Pokémon is booming and easy to make money in - if you know just a tiny bit of what you’re doing. But if there isn’t any love for the hobby, I doubt any of them will make it long-term. Just my 2c, though.
Short-term hype vs actual investment. The term ‘investment’ is meant to be a multi-year plan, yet a lot of people who call themselves ‘Pokémon investors’ are nothing more than scalpers and flippers, here to make a quick buck. And although it regrettably doesn’t happen too much anymore, some cards will quickly increase in value at first, but will eventually decrease in value once the initial hype dies down. So if these ‘investor-kiddos’ bought in at the wrong time, they might actually be losing money with their flips instead of gaining anything.
100% collectibles that happen to be investments. Pokémon cards have been around for 30 years, and although it has been investments to some people, that term wasn’t even used until just before Covid in 2018/2019..
Pokémon cards are, and will always be, a collectible. That they can be used to make money in terms of investments, is a nice plus for those who want to gain money this way. But that will never been what it is primarily.
Their collectability and the nice artworks. As well as the TCG game, even though I’ve never played it personally.
To flip it around, if it weren’t for us collectors still wanting to collect our cardboard even in this higher-value market, there wouldn’t be any way to invest in it in the first place. It would just be another one of those NFT scam worlds, that would die out within a year or two.. Without collectors to keep the demand part of the ‘supply and demand’ in place, the pure investor bros wouldn’t have any way to invest in Pokémon to begin with..
Greetz,
Quuador