I just want to chip in that the definition of "disabled" is more complex than just receiving disability benefits. I'm going to use a UK framework to illustrate what I mean, but my overall argument applies equally to other countries.

There are multiple different kinds of disability benefit in the UK. One of them (PIP) isn't dependent on household income, and isn't linked to one's ability to work. ESA is another disability benefit which does depend on income and is also linked to difficulty working. You can get both PIP and ESA, but it's fairly common for people to get PIP, but not ESA. Being in receipt of either of these benefits would potentially qualify a person as being "disabled"

These benefits are also used for gaining access to other resources for disabled people, like a blue parking badge that allows one to park in disabled bays. The easiest way to get one of those is to provide evidence of being in receipt of a benefit such as PIP, but you don't actually have to be in receipt of any benefit to get a blue badge (and once you do have a blue badge, that is often sufficient 'proof of disability')

And to complicate things further, if we are talking about disability discrimination, then a person doesn't need to be in receipt of any of these benefits to be covered by the Equality Act. Many people who don't even think of themselves as disabled are covered by this legislation, which casts a very wide definition of "disabled".

The TL;DR: is that even the concept of "legally disabled" is complex and context dependent.