I'm sure I'll do a V-8 smack....

[Kajenkids]

But what the heck is the difference between all the creatively, yet oh-so-unhelpfully named sewing machine feet? Why does it matter what I use and what are the correct applications for each?

Just call me befuddled...
Kathe

[Hulamoon]

That's a big question! You need to do a little research

https://www.google.com/search?q=sewi...w=1093&bih=498

[Alpha O]

Here's one list:
Machine Feet tutorials - The Sewing Forum

and another:
Sewing tutorials: Use of special sewing feet

[K. McEuen]

Even with all the tutorials available out there probably the best reference for your particular machine and the feet that came with it is your owners manual.

[Alpha O]

I've never seen a tutorial for a narrow hem foot in a manual that has much info on the way to get it started.

Most manuals are black and white. If you can find a color stitch guide it can be easier to trace which thread is which - especially with sergers.

The manual with the Babylock Coverstitch is very sparse. If you want to know about the feet - you need the Evolve manual or foot workbook.

The manual for the PQ1500S is very sparse, too, especially if you want to use it for more than quilting.

Babylock used to sell workbooks for machines - pricey, but far better instructions and techniques than in the manual.
Pfaff, Viking and Bernina seem to have a foot for everything. Babylock and Brother don't. The BL workbook had some very good workarounds for the lack of the specialty feet.

A lot of information is now online and you have to print it to keep a copy by the machine for reference. I prefer printed. Can't bookmark a spot in a tutorial and just go to it.