Bazel doesn't have any user-facing java dependency.

> what real extra benefit Bazel brings in here

Builds are hermetic by default, so unless the developer chooses to escape the sandbox, everything is guaranteed to build on other machines with no additional setup.

(Also, I genuinely hate when I have to manually install build dependencies system-wide and pray that there will not be any conflicts. Having everything pinned to specific sha256 or git hashes by design is a breath of fresh air)