Best practices: Use of a single private key as a person, or multiple to identify self across domains?

Best practices: Use of a single private key as a person, or multiple to identify self across domains?

Similar to the question here, I'd like to apply the same question to a person.

For example, I have implanted a chip in my hand¹ that holds an encrypted private key that serves as my personal unique identifier. As it is tied to my person physically, I have just a single origin for the key it holds.

I currently use this key to authenticate with my own servers. What I'd like to do is register this key's public component for use at work.

• Assuming that the key itself is adequately secure,² what vulnerabilities does this expose to my key and the servers I use it with?
• Should I consider creating additional private keys to identify me?

_{¹ Yes, I actually did this.
² The two prime numbers were generated on an offline computer, then transferred to the chip encrypted using a serial NFC read/writer.}