Problems caught early are much easier to fix than problems caught later. This applies to any project (I’m not a programmer, but an engineer in the traditional sense).
Just “doing it” without coordination and review is a great way to waste a bunch of effort down the line with re-work.
Edit: typo
The rest of the world would like a word. Do you really think only you people in the US exist?
Also the equivalent for psi is Pa (=N/m²), usually as kPa or bar (100 kPa).
Most people don’t really understand either to a great extent, and are just familiar with one or the other.
As always though, metric wins because of its interoperability with all the other metric units.