As a $3 Digger, Sage is probably more effective than Huckster, as it has +1 action and doesn't require having two $3 terminals collide.
As a means of reusing your best cards every turn, Scheme is better, because it's also a cantrip.
The Huckster collision might be useful if you're drawing your whole deck every turn--but if that's the case, Scheme or Scavenger would probably produce similar results while having stronger vanilla effects.
The reaction is Ok against Thief-type effects, but on the whole I'd prefer Secret Chamber's reaction. Even though SC only looks at two cards rather than your whole discard pile, it works even when its draw doesn't trigger a reshuffle, and it will usually have a similar effect.
Finally, this mechanic would be really time-consuming in IRL play, especially multiplayer. That's why Secret Chamber, Thief, etc only look at the top two cards, and Rabble only hits three cards.