The sanctions do not fullfil its purpose which is to overthrow the castro regime. On the contrary, the sanctions undermine the country's socio- economic progress. They also violate the rights of American citizens while depriving them the freedom to travel and make friendship relations with people of their own choice.
Sanctions harm Cubans and the Cuban economy. Part of the reason behind sanctions was to put pressure on the Cuban economy and pressure to change political stances. The US is very close to Cuba distance wise, and the embargo hinders economic growth and tourism as well as foreign investment. It also gives the Cuban government a chance to blame economic failure, at least in part, on the US.
Cubans lack necessary everyday items because of sanctions. Medical and food supplies are in short supply because the country cannot produce enough for its people. The quality of life would increase dramatically for the Cuban people if they could trade with other friendly countries. The US only keeps sanctions because the president needs to win Florida's electors.