I teach shell scripting. Cat invocations are cheap and help learners understand and keep clear where input is coming from, and where it is going. There are no awards or benefits to reducing the number of lines, commands invoked, or finding the shortest possible way to perform a task in a script. There are plenty of detriments to reading and understanding though when we try to obfuscate this to save 1ms of execution time on a script that is going to execute near instantaneously anyways.

In short, I straight up don't care.