I’m glad to hear you’re enjoying the course and thanks for the tip! Speaking of OCD, I’ve learned over the years that auto-fill tools don’t always get it right, sometimes filling in places I don’t want it to fill. So my habit is to fill holes one by one usually.
There’s nothing wrong with using auto-fill tools but it’s probable that some mesh errors may have to be fixed a later. Whether we do it correctly now one-by-one or fix potential issues later it’s a similar maintenance effort either way.