If nothing else Abseil gives you state-of-the-art hashmaps that run circles around the STL ones, which are slow pretty much by definition. The spec precludes the modern ways of implementing them.
https://stackoverflow.com/a/42588384/1593077
But you can and should use non-std state-of-the-art hashmaps without living in the world of abseil.
Chromium uses hundreds of other open source libraries. Is there something about Abseil specifically that sticks in your craw?