They have some similar duties but they're not safeties. I know they're similar but there are differences in the defense. Call Fred Warner a safety and see if he'd agree.
One single guy claimed this. Far more people outside of CB have said the exact opposite. Getting more LBs on the field. Between the Kaufusi's, Pili, Wilgar, Tooley, Ah You, Bywater, Tanuvasa, Fonua, and others, they're not putting, 2 out there.