The coins may be legal tender, but they were minted in clear violation of federal law.
Federal law (31 USC 5114) unequivocally states: “Only the portrait of a deceased individual may appear on United States currency and securities.”
(And yes, coins are legal tender and are considered to be currency.)
This law has not been repealed and is still in effect. Trump is breaking the law yet again.
Scott Bessent has tried to obfuscate the issue by pointing to a commemorative coin issued over a century ago that featured Calvin Coolidge, but Congress passed a law then specifically allowing it (which was also controversial at the time). The current Congress has not authorized an exception for the Trump coin.