The game takes a lot from Pokémon + Yu-Gi-Oh! + Magic, there's an extensive testing team both in-house and with select players, so the game is fun - for people that actually play TCGs! Elestrals Clash is in development, which is their digital client, so once that releases she can learn from there. It plans on using the pre-Runeterra Maintenance Mode monetization structure: all cards are free, paid cosmetics. From the current beta, they advertise their physical product and upcoming releases on the start page, so think of it as a way to get people into the game (and eventually buying actual cards).
As for collecting, Pippa has her work cut out for her. There are x/10, x/99, and as of the upcoming Firestorm set, x/25 cards (with variations of numbering such as x/1 for tournament prizing); these are numbered cards, meaning there will only ever be that amount in circulation (except for a printing error in the Frostfall set). They can be in any pack of cards that are opened, incentivizing purchasing physical product + supporting the game. This is further extended starting with the Firestorm set, where there is the possibility of any pack being a x/99 "God Pack" that's entirely made of cards that can't be obtained every other way! Excellent for trading at in-person events as well! That being said, there are certified psychopaths that are dead-set on obtaining multiple copies of those cards, so watch out!
EDIT: There are also cards that are exclusively obtained from participating in tournaments, or going into your local game store, so she'll need to put on her gay shoes and get some legwork in.