How can I really see the benefits of 10-bit footage?
REC 709, the current standard for HD delivery (and YouTube), really only requires 5 stops of dynamic range (since the legal range is 16..235 out of a full scale 8-bit encoding 0..255).  Now, in much the same way that a 2x4 piece of lumber is milled from a starting point of 2"x4" down to 1.5"x3.5", an 8-bit encoding gives one the freedom to shave down the highest and lowest bits (where noise lives in the shadows and where clipping occurs in the highlights) and still have one more bit of slop to adjust brightness.  Which is not very much room to be creative.

A 10-bit source file allows for two bits more dynamic range that can be used to pull down highlights or lift shadows.  That may not sound like very much, but against a delivery format that encodes a total of 5 bits, it's quite a lot!

Now, it's true that with careful processing (especially noise reduction), one can make more use of the top and bottom bits of dynamic range, which means even more opportunity to stretch the dynamic range of the source material to conform to the intended tonal range of the output format.

Another place where 10 bits becomes essential is in the world of HDR video.  YouTube now supports HDR playback on devices that support HDR10 (and Dolby PQ).  HDR 10 really does can use all 10 bits of dynamic range, but as Ansel Adams teaches in his books on The Zone System (The Camera, The Negative, The Print), the art of photography (drawing with light) is not merely creating a 1:1 mapping between acquisition and exposition, but in how one chooses to distribute the tonal range to best effect.  Starting with a full tonal range in the source makes it that much easier to push things around to get them where you want them to be on output.