Lethal Scheme isnt the most efficient kill spell, but it does hit planewalkers (big plus for Commander)
However, its lower levels of annihilation (unless weakened) puts it at a meta position lower than not just the insane Mega Charizard Y EX, but also Mega Blaziken EX
Protection from red is already incredibly annoying for red decks, and saving your board from a pesky Anger of the Gods has made this a popular sideboard card over the years
Preconstructed decks, or precons, are a great place to start, and will help you understand the bare bones of what should be in a deck
Its still a Standard staple, but the meta has already started to adapt with sideboard hate like Torpor Orb, cooling off the frantic pressure to own a playset at any cost