I actually quite enjoy making part recordings. I like getting inside the music in a different way. I like finding out what the pitfalls are before my students find them. I like the work involved in creating something of use for my students. I like using my skills and gear on behalf of my students. I also find that, with my own musical works, I discover and change things in the recording process that I wouldn’t have found as quickly otherwise.
And most importantly, I like giving tools to my students that help them grow and develop as musicians, even if they don’t have keyboard skills. Because my students are not all destined to become professional musicians, I think practice part recordings are a great tool to empower students to practice beyond their rehearsals.
(I also use Melodyne indiscriminately to speed up my process. As long as I sing without too much vibrato, it’s a cinch to quickly make a well-tuned part recording.)