I don't think saving time is the issue? Copy or downloading to your Computer (PC or Apple) won't make any difference in the image.

Several possible explanantion for this comment that could range from innocent to cynical.

Could be a question came up in the conversation that the employee didn't fully understand?

Could be someone wants to sell more memory cards?

You can always reload the xD card (or any memory card for that matter) from your computer.
They are handy to carry in and use. I've bought several small 32-64M size to run in and get quick prints or just to hand to the lab.

Should never be degradation (unless a change is made in the file with software) in digital formats.
Do remember that if you edit, save only the final image as a JPEG. Each JPEG compression cycle will degrade the image. Intermediate or works in progress save only as TIFF or BMP (or the internal to your software like PSD in Photoshop).

Good luck - C