You bring up a good point about naming.
However, I think the original issue still stands:
"I am not sure why a person would save a template image using this script if they weren't trying to use it in their spine file."
Is there a better solution than just naming the slot 'template'?
edit: Now that I'm thinking about it....isn't this already an issue? The script saves template.png. Well, what if I had a slot named template. Then, the slot would save over the template, and the result would be no template image. The script wouldn't be doing what it said it would when I ticked the box. A lesser problem than the one you pointed out, and definitely an edge case. Perhaps the script could check to see if any layers were named 'template' before starting.