Is there any technical difference either way between formatting or deleting files from an SD card? Currently I transfer off card, reinsert to camera and format for next job (daily). I am just wondering if I am damaging or wearing out anything doing it this way as opposed to simply deleting files.

Formatting is recommended over deleting, though the difference between the two is actually kind of small:

Deleting merely marks the space as available to write over.

Formatting actually deletes the file system that tells your computer where the data is located.

If you think of your SD card as a Book, and your Movies//Photos as Chapters in the book:

Deleting individual files is like going to the Table of Contents and erasing the page number of each chapter
Formatting your SD card is like deleting the entire Table of Contents and writing a new blank TOC.

In either case, your old data is still there, it is just a candidate to be overwritten.
Formatting is usually preferred because it is one simple operation

There are 10 year old white-papers that talk about the wearing-out of memory cards.
We are talking in excess of 1 million write-cycles.
I wouldn't worry about electronically wearing out your SD Card