And clues are permanents, something that sometimes matters (tangles, stax...). Master of Etherium could have place in a deck with this also :p
They are artifacts
Yes, that is why I say they interact with tangle, smokestack and master of etherium. Of course I'm not saying to play them all (master was a bad suggestion and tangle/stax do currently not belong to a deck playing other blue creatures than metatmorpth), but they were just examples. Tolarian on the other hand seems more interesting. Welder can also benefit, and there could pop more ideas.
I find attractive the idea of creating artifact drawing tokens, but I don't think they would be competitive. If they do (in standard likely), this card is interesting:
Daring Sleuth 1U
Creature - Human Rogue
When you sacrifice a Clue, transform Daring Sleuth.
2/1
Bearer of Overwhelming Truths
Creature - Human Wizard
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Bearer of Overwhelming Truths deals combat damage to a player, investigate. (Put a colorless Clue artifact token onto the battlefield with "2, Sacrifice this artifact: Draw a card.")
3/2
A 3/2 creature with prowess that creates drawing tokens could be played if it costed

. The original card is not playable by any means, and at this point I really doubt any will be vintage playable.