USDC is a centralized stablecoin backed by USD reserves held by a licensed custodian (Circle).
USDC.multi is a large-cap undercollateralized asset. This asset depends on a centralized entity for custody services. This asset is exposed to the underlying risks of Multichain, a protocol rated as Watch out.
USDC.multi is a stablecoin that usually trades within 20bps of its peg to USD, which makes it a solid store of value.
USDC.multi has an uncapped supply but has inflation control or burn mechanisms in place.