In my early days, starting in 2003, iStock was the only agency that would carry clipping paths through the JPEG images. For images sold resized they even resized the clipping paths for a few years. Clipping was an added value for customers who wanted items on a page with close surrounding text and who wanted images to drop into other pictures. Unfortunately, iS subject policy changes has killed my niche of clipped subjects, so in 2020 I don't know the current value of doing the work of clipping. I also don't know if any agencies carry the clipping paths through the JPEG files today. You may just have to try some and watch for a year to see if they have better selling than  your non-clipped images. Submit both so you have a like subject reference point.