It's not a particularly useful card in a mono-green deck, but Bloom Tender becomes pretty powerful in multi-coloured decks
6 Kefka, Court Mage Players Will Be Dancing Mad When The Clown Enters The Field Discarding can be a major nightmare in Magic: The Gathering, especially when facing something without a lot of drawing power, like a blue deck
Spot removals: In general I always start my decks with 5 to 7 spot removals for creatures, artifacts, enchantments, counterspells etc
And the price is still less than two individual FlipNTray 100s, which only fit one deck each
Mirari's Wake faces more competition and interaction these days, but its still powerful
The only difference is Comet uses these symbols in the effects of his abilities rather than the costs