I understand how generating a SHA-256 hash containing any specified sequence requires lots of guessing and checking. The longer the specified sequence, the more rarely that it will appear.
And I understand how inserting random nonces into a block until its hash happens to begin with a certain number of
0s is a computationally expensive and ultimately random process, which demonstrates proof of work.
What I’m wondering is: why zeroes, and why leading?
Could mining work just as feasibly if the challenge were to produce a hash with, say, ends in a certain number of
Fs, or has the digits
314159265358979... starting at index 32?
Or is there a technical reason why miners’ goal is to produce a hash which begins with
0s, and not any other character at any other location in the hash?