I guess I’m coming at it from an optimizing market data provider perspective once you preallocate memory the next thing to optimize is the string decimal conversion if the feed isnt binary encoded

It might be your least concern, and that's fine but it's not the least concern for many people who need to process large volumes of transactions.

Money, even within fintech, is a concept used across a wide variety of domains, and you can't assume that what concerns you is what concerns everyone else relying on it elsewhere.

They specifically mentioned HFT so I suspect they care a lot about processing speed