Proof 1937 Mercury Dime - Obverse/Reverse Image Offset Questions

Hello, everyone:

I'm new to Coin Community, and this is my first post.

I recently purchased a proof 1937 Mercury dime from an online dealer. Upon receipt, I noticed that the reverse image was offset by about twenty degrees from the obverse image.

In my experience, I have never seen a US coin of any type struck like this; thus, unsurprisingly, my initial reaction was, "Jackpot! Ka-ching!" But after doing some research, I found that this mismatch is normal for these coins, proof and otherwise, but varying by degrees.

This raised a few questions in my mind:
[1] Why were these coins minted like this?
[2] Do any other US coins display this "feature"?

Thanks much.