It's a cool talk, but the relevance to the present problem escapes me.

If you're alluding to gcc vs fbstring's performance (circa 15:43), then the performance improvement is not because fbstring is faster/simpler, but due to a foundational gcc design decision to always use the heap for string variables. Also, at around 16:40, the speaker concedes that gcc's simpler size() implementation runs significantly faster (3x faster at 0.3 ns) when the test conditions are different.