Emergency use authorization for the vaccines was granted because it is an emergency, and the normal lengthy wait for possible longer-term side effects was judged to be riskier (and causing more lives to be lost) than not granting EUA.

There's a big difference between something like a shingles vaccine -- and as it turned out, they did NOT wait long enough to discover side effects that the first one had, which caused it to be withdrawn -- and a fast-moving, highly infectious and often fatal or debilitating disease like COVID. I do not recall ever reading that an issue in the EUA for vaccine was due to a lack of therapeutics.