They can be crocheted, I made some like WAY way back in the day!!! I used sport weight yarn and a size "E" crochet hook. Would probably have worked better on a steel size 5 or 3 (in steel crochet hooks the bigger the number the smaller the hook). Personally, if you use the smaller hooks and sock yarn or even crochet thread (size 3 or 5) I don't think it would feel any different than the purl bumps one already has on the inside of their sox if they were knitted. It's just a different way of arriving at the same thing. Socks!!
Aww heck, after you've gotten the foot done (crochet sox for the most part would be worked toe up) and the heel turned, you could have all kinds of fun on the cuff. You could use tapestry crochet for colorwork, or crocheted aran cables and bobbles or you could make lace pineapples or shells or popcorns or dang there are hundreds of things you could do. Heck you could even make the leg of the sock look like granny squares or you could make granny squares and sew them together and pic up and work the foot. It's all up to one's imagination. As long as you have the necessary things taken care of. Toe, heel, and leg or cuff. Whatever you do with the rest of the sock is totally up to the person making them.