This move makes a mockery of U.S. foreign policy and its commitment to democracy and human rights. President Trump is known to be susceptible to personal flattery, which appears to be the only motivation for removing sanctions on a military dictatorship. This does not bode well for America's standing in the world and its ability to stand up to autocracy and illiberalism.
Sanctions are the favorite tool of the U.S. when trying to strong-arm a nation to change its behavior, but they have seen diminishing returns in recent years. Affected nations can grow resistant to sanctions and see the powers that be get more entrenched while the general population suffers from the economic deprivation. Rethinking sanctions can be an effective move.