Diminishing Returns used to be played in Type II with Mind Over Matter and Grim Monolith in a way similar to the Extended decks with 4 Time Spirals.
Before that, it was played in Type I.5 multi-colored weenie decks as a drawing engine that replaced restricted powerhouses like Wheel of Fortune and Timetwister.
Diminishing Returns is a powerful card advantage tool, and forget the ten cards because you may not have drawn them anyway (unless you have one-of-each cards to tutor for or can't risk losing certain cards in the deck).
Weenie decks are redundant in terms of components, and empty their hands fast enough to warrant the card drawing. Try it in something like a blue weenie and see if you like it better than Coastal Piracy.
Of course, it used to be played in U/G/R decks, so you used to be able to draw Bolts off it, also, so I'm not sure if you'll find it as powerful in the present Type II.