Thats fine, but do you understand the point that, by putting these utilities into a shell script, you're negating the ability to search for common commands through history, and now also need to load up your working memory with the name of the script, where it's located and so on?

I do put bigger/heftier utility functions into shell scripts - its just that I, more often than not, forget where they are and have to go searching. But with Ctrl-R, the flow does not get interrupted.

Anyway, not arguing for/against either technique - they are both appropriate when needed.