The doc comment on the method has the following statement.

GEP is very likely to segfault if indexes are used incorrectly, and is therefore an unsafe function. Maybe we can change this in the future.

Wrong GEP indices leads to asserts (on debug builds of LLVM), and is perhaps a good enough reason to not have unsafe for this method.

Alternatively, a new inkwell datatype can be introduced for GEP indices, to make them safer. Something similar was done in Haskell. See https://luctielen.com/posts/making_llvm_gep_safer_in_haskell/.