According to PSA, only 478 copies of the Nintedo Ancient Mew card have been graded at a Gem Mint 10 level, with 2,255 copies of the card graded in any condition
You could set up a strong double or triple-block and get rid of a powerful creature while keeping all of yours
This makes the Lorcana Gateway Box a great way to teach people how to win by having them do it, and while it might be a little bit hands on, certainly compared to most games, its a great way to work around the sink or swim mentality that needs to be employed when you join a game that has been running for several years and has stacked more and more mechanics into it
Speaking of synergies, The Reality Chip offers card advantage and deck manipulation
Novice players may start with a modest collection, but as they collect cards by the dozens or hundreds, they'll realize that not every card can be put into their competitive deck