Yes. `Hierarchy` has a lot of overhead e.g. extra loops, extra function calls, merging results together. It also makes a lot of assumptions about expiration times in higher backends that aren't accurate. Having direct access to the array allows for some optimizations (in `getMultiple()` in particular) as well as more assumptions about how it will be used.

You can see performance improvements in the benchmarks at the bottom of the [CI output](https://travis-ci.org/iFixit/Matryoshka/jobs/23404119). Compare `MemArrayMemcacheHier` to `LocalMemcache`.