The biggest is that the pandemic has slowed down the production and distribution of physical cards, creating a scarcity in stores
This means your opponents could stop you with a counterspell or instant-speed win condition of their own
It has protection from red, which means that a card like Pyroclasm would have its damage prevented, the Knight cant be enchanted by Aspect of Manticore or equipped with Embercleave, it cant be blocked by any red creatures, and it cant be targeted by spells like Academic Dispute
Galarian Zigzagoon rotates, but Hawlucha is a worthy replacement, being able to put two damage counters on the opponents board, albeit only on the Bench
Yes, battle cards are like any other card type and go in your deck
For collectors, EB-01 remains a strong buy at the JPN price point (~$100 per box)