That option is rarely taken so I give an advantage to cascade as the stronger mechanic, and the fact that Magic R&D is less likely to bring it back makes it more rare and hints that it is better than discover
These are unique cards to championship decks that Wizards used to sell, which are explicitly not legal in a tournament setting
Old Erebos is singularly unimpressed by new Heliods jank, and happy to sweeten the deal with reliable draw for a modest fee of mana and life
Thats plenty of sorceries, instants and enchantments covered
In this case, flipping doesn't mean throwing the card in circles from one foot about the playing area like with Chaos Orb
The higher you go, the less likely your opponents are to win via attacking, but I imagine theres a sweet spot around Bracket 2/3 where this really shines