Some of the reprints will feature new illustrations, so still a reason for those with near-complete collections to open packs, and there may even be some brand new cards to collect, although that isn't confirmed in the trailer
They usually have the strongest attacks, and most useful abilities that can flip the game state the moment they hit the field
The combo is a bit convoluted but only involves two cards: Goro-Goro and Satoru and Breath of Fury
This was a format dominated by midrange decks, each with their own upsides and unique play patterns, leaning further into control, aggro, or even stun
If you want Mega Evolution products, TCGPlayer is the most straightforward path, while retail sites are little more than a distraction