Cheating out creatures with great ETB effects or something like Etali, Primal Storm with a powerful attack trigger is well worth the 3 mana
Nobody in the game can cast noncreature spells that cost four or more mana, and nobody can cast spells with X in the casting cost
Other factors for budding collectors include investment potential, many consider Pokmon cards a worthwhile and potentially fruitful investment, as long as you know what you're doing, though remember this is not investment advice
Collected Company in the main phase to play around an opponents Spell Queller
They typically say something along the lines of whenever you draw a card and there are even cards that care about when you draw your second card each turn but those get their own list and you absolutely should read it after this one
But as the format starts to coalesce more and decks become more purposeful, Thoughtseize's stock only stands to rise