Thanks to ward 2, Ratadrabik himself is a bit of a pain for opponents to get rid of
Legality depends on the tournament format -- Fish and Bids can be legal in some formats and banned or restricted in others
In this case, the effect is...quite solid
However, this just makes it easier to allocate Energy to other Pokemon while Dedenne does its work in halting your opponents progress
Most black decks that dont want to win through combat or combos are going to be winning with life drain, whether thats through intricate graveyard shenanigans, aristocrats, or just pumping a bunch of mana into a spell
Cards like Ideas Unbound and Avaricious Dragon require you to discard at the end of the turn, and ending the turn before that lets you keep the extra cards