Consistent combat triggers keep hands full and maintain pressure across multiplayer tables
Loxi: I know they did the kicker cost for flavor here but yeah
Each Secret Lair could focus on a particular game or theme for example, one might feature Final Fantasy XIIIs cast (Lightning, et al.), another could highlight Final Fantasy XVs heroes , and perhaps a third could be a fun roundup of iconic Chocobos, Moogles, or Cids from across the series (the possibilities are endless, but the speculation of a 15 different Cids Secret Lair has already made rounds in the community in jest!)
For anyone with a young collection on Arena, a preconstructed deck can be a huge leap up from Arena's provided decks
What Should Be in a MTG Commander Deck
They may be good in very specific or very niche situations but you would almost never seriously consider putting them in a competitive deck