Any system that is predicated on "one X per person" needs to ensure that a single human can't synthesize multiple "persons" in order to get more than one X and cheat the system.

Systems like this include:

* Democracy: One vote per person.

* Universal basic income: One income voucher per person.

* Some sales: One coupon per person, or one purchase per person.

* Many resource usage licenses: Can only catch one salmon on this river per person, etc.

Basically, it's good to have systems that are fair and equitable and in many cases, a way to do that is to distribute the good uniformly to people. That requires you to accurately determine how much each person gets, which requires a reliable notion of person.

At the same time, I think Worldcoin is complete nonsense. Almost all of the above systems function much better when scoped to a smaller regulatory authority that already has an existing reliable notion of person: passport, driver's license number, etc.

If you could make arbitrarily large numbers of accounts that each receive the token, that would break the system

Yeah, this is pretty obvious. I don't know that the phrase "fundamental rate limiter" can be used to describe a solution to this problem. Maybe it's me but it seems very odd choice of words.