Personally I love them, and the artwork with Hildas Supporter Full Art is just cool to look at
Sure, it costs five mana to do which is not cost efficient, but this just means you are not doing it till it is really good to do so or you have little else
For example, suppose you control Infesting Radroach, a 2/2 creature
Type: Null 069/084 Colourless Type: Null Colorless HP110 Basic Pokmon
Mew Prime pokegym.netMew Prime is also another Basic Pokmon but with a less desirable stat than Absol Prime
Special Summon 3 Level 5 or lower WATER or WIND Dinosaur monsters from your Deck in Defense Position, but their effects are negated, also for the rest of the turn, you cannot Special Summon monsters from the Extra Deck, except Dinosaur or Sea Serpent monsters.