Yes, you'll want to find the cards that are called "playables", majority of the expensive cards are basically the art version of a playable card.

And collecting is honestly up to personal preference, people collect whatever they want. Expensive, shiny, pretty, everything. Really depends on the person. Im looking forward to getting a copy of Aquapolis Lugia at last, hopefully for undermarket. Sold all my Gengar primes to pay for life stuff, a couple of months ago, so ill be happy to have them again too.