Heres what red usually brings to the table: Burn Red is the main color for cards that deal direct damage to targets, and this includes classics like Lightning Bolt and Fireball
While Submerge only bounces creatures, the fact that it puts them on top of the library can be a big tempo loss when someone's getting out of hand
The allure is in the acquisition of a graded card without having to go through the often lengthy grading process, wherein you have to manually send off your cards and wait to hear back
Its functionally similar to Two-Headed Giant in some ways, and itll be interesting to see how some of the more collaborative cards featured in Team-Up function in that game format or even in Commander, where it might behoove you to help out an opponent to take down another
Cards like Field Trip, Cultivate, Letter of Acceptance, and similar cards from non- Strixhaven sets do a good job at providing extra mana if you need it