Performance public service announcement.
Benchmark is included below for those who want to validate this discovery. "Type Cast" works by flattening the type to string and then unflattening. In this case, it doesn't recognize the special case of the byte array already being a string, but the Byte Array To String node does recognize that equivalence, so doing this eliminates a significant part of the type cast effort.
This has been reported to NI as a possibility for future optimization.
array-typecast-benchmark.vi