Second Harvest may be cast the turn before it's time to attack for lethal, giving the opponent just one turn to get ready before the Elvish onslaught begins
Fortunately, some good guidelines apply: Delver/otherwise spells matter : Surgical Extraction, Grafdiggers Cage, Nihil Spellbomb Eldrazi/Lands/Combo (not predicated on critical mass and/or no hope of beating you otherwise)/Fringe Stuff Played By Person At Your Store With a Full Sleeve Tattoo and Black Flag T-Shirt: Leyline of the Void Artifact Synergy/Karn, the Great Creator Prison : Tormods Crypt, Relic of Progenitus, etc
The combined result of these two abilities will be an endless war, fought among your opponents but not involving you, giving you ample opportunities to plot, scheme, and pick the bones of your fallen foes for card advantage
Most likely, he will do well in the 99 of a blink commander to accrue value
Foil cards are inherently rarer than non-foil cards, etched or otherwise, which bumps their value up
Maybe its not revelatory to point out how good it is to get a bunch of triggers off someone cracking a fetch land, but it is a pretty massive upside to building around one of Magic s foundational mechanics