Agreed, it's a feature that is truly a hidden gem at the moment. And it's precisely for that reason that I don't quite understand why it hasn't been more loudly proclaimed as a distinctive offering of the steem blockchain by Steemit Inc.

SP delegation affords users the chance to be rewarded with a steady cash flow in exchange for essentially committing to holding their steem as SP. In so doing, it actually serves to reduce the amount of steem that can be traded on the internal market and on exchanges. This indirectly supports the value of steem and sustains price rallies due to its influence on supply and demand: the supply of steem becomes more limited and the demand correspondingly grows as more users seek to purchase it in order to power up and delegate!

So while the steem blockchain has a predefined inflation rate, that can be mitigated by more users holding steem as SP. What better way to encourage this than to highlight SP delegation? It has further fostered a free and competitive market here on steemit whereby voting services, steem based platforms, and general users all compete to be SP delegatees; one quickly realizes that there are differences in what these delegatees are willing to pay to borrow your idle voting power (and what they intend to use it and the earnings from it for) and delegators have the flexibility to delegate it out accordingly.

I would hope that in future updates of the platform itself, the delegation tool is built into user wallets. When I first learned about it myself just recently, I had to do some digging on how to actually tap into this best kept secret. I ended up using @justyy's SP delegation tool after stumbling upon it. It should be made simpler to both find and utilize for all users. I'm still adjusting to it and have more to learn.