Many politicians believe that when someone with a disability is married, it's the job of the spouse to pay for their disabled spouse's survival and thus PwD lose their SSI checks as a result of marriage and thus often "choose" to remain unmarried.
Unconditional Basic Income would change this. Marriage would never mean loss of one's UBI.
Also, because everyone gets UBI, no one with a disability would not get it, whereas with SSI, 4 out of 5 PwD don't get it.