Plain enlargement spreads existing pixels over a bigger area, which makes an image soft. Upscaling estimates the detail that a larger capture would have shown, using what is in the picture: the direction of a weave, the line of a seam, the edge of a button. The result holds up when a shopper zooms.
It has a firm limit: it works from what the photo contains. Herofab's Upscale tool raises the resolution two or four times and is briefed to sharpen what the photo holds without inventing new features and without altering printed text, so a label that was blurred in the source stays unreadable.
Upscaling is the answer when an image is good but too small for a marketplace's minimum or for zoom. It is not a repair for a photo that is out of focus or badly lit, and the upscaled image should be compared with the product in the places where detail matters: text, logos and fine patterns.