https://www.thenation.com/article/society/ssi-rules-families-poverty/
The Supplemental Security Income program (SSI) was created in 1972 under the Nixon administration to provide financial support to low-income seniors and disabled people. An effort to federalize state-level adult support programs across the country, SSI is a means-tested program—there are financial requirements to be eligible. In the case of SSI, as of its last adjustment in 1989, enrollees cannot have savings of more than $2,000 as an individual or $3,000 as a family. Furthermore, SSI beneficiaries are prohibited from having retirement accounts, life insurance policies, certain types of personal property, funeral/burial policies, and access to other types of income.
[emphasis mine]
OMG I'm gonna test some means! 
Oh hey this is me! I can't work at all because my disability basically gives me about four hours out of the day where I can sit up, if that. SSDI pays a little under working a 20 hour workweek for me, so it's either: work part-time and feel physically awful or not work and get a low amount of money I'm not allowed to save or invest with.
Any side hustles like doing art commissions or gig work also mean having to pay back what I made or else I lose all benefits. Basically that means doing free labor because I end up with zero more dollars and that's not far from scabbing.
My retirement plan is global warming.