What's great about Abundance is that it allows you to be able to not draw a land if you want to. It also allows you to draw a land if you do want. In a format like Commander, Abundance can be invaluable. Getting mana-screwed (not enough land to play your spells) or mana-flooded (too many lands and not enough spells) are common issues in the format. This Enchantment offers very useful card selection, although, it is a bit mana-intensive for a highly competitive format like Modern.
Despite not seeing play in top tournament play, Abundance is a highly sought after card due to having such a useful effect. Green decks often have access to more than 4 mana on turn 4, so this can come down as early as turn 2 in some decks. Abundance was a nearly $4 card before the Duel Deck reprint and it's still creeping back up. While you can't expect to see this card in a top 8 Modern deck, Abundance is a great card that you shouldn't overlook in a trade binder.