If youre worried about build time (which is usually about 50 minutes), you can mitigate time anxieties by having a baseline done early (i.e., I know Im playing UB because I have Edgar, Sephiroth, Odin, and Ultimecia, Time Sorceress, but should I splash red for anything?)
720.2a If an effect refers to a card, spell, or permanent that has an Omen, it refers to an object that has the alternative characteristics of an Omen spell, even if the object currently doesnt use them
It phases out
There are a lot of themed decks that use this card and most especially in Commander, so much so that you'd be crazy not to include this card in your deck
Lets dig in
Description : Mystic Remora is an enchantment with a cumulative upkeep cost that allows you to draw a card whenever an opponent casts a noncreature spell unless that opponent pays four mana