A genuine ungraded copy in near mint condition would be worth anywhere around $10,000-$15,000 these days, while an extremely rare PSA 10 version would sell for upwards for $50,000 easily
In 1v1 formats, its essentially a waste of your mana and your time, but when you have three opponents actively casting spells each turn, Rhystic Study transforms into a powerful draw engine
Even though this lets you pay life, its mana production is the real star
You can always build a completely unplayable thematic deck if you want to
Im not sure how this card will fit into previous Pokemon online decks or new decks, but I think it will be a viable card along the way for sure
As I mentioned, one has reportedly already sold for $10,000-$15,000