It's actually not a bad idea. I personally use an encrypted archive file to store my more sensitive things like keys, but having something dedicated to the Blockland keys would actually be really nice an convenient compared to an encrypted text file.
except, like, nobody is out there hacking people just to get bl auth keys
protect more important stuff like steam passwords n such, sure, but BL auth key? if someone really hacked my bl key i'd just give it up and get a new key, after uncovering the perp who took the key from me.
plus those who do know how to protect their keys securely probably don't hold grudges against those who know how to actually hack.