Rarity refers to how likely the card is to be opened in a booster pack
It's probably a little early to make predictions about whether these Mega Evolution cards will generate the same level of unhinged hype as the current newest Pokemon set, Prismatic Evolutions, but the 2025 release window certainly means it's going to be a busy year
A quick note: a Magic: The Gathering card is defined as having a Magic card front and back, typically with the brown almost book-like design on the back, with exceptions for double-sided cards
Instead, it's likely that Wizards collects player data, and gives cards a ranking according to how many wins and losses their decks rack up (no doubt that's not the only factor, there's probably some other arcane number crunching too)
Dragon Shield seals the deal with its price, which budget-constrained MTG players will like