As previous answers suggest: These hooks tend to come with most hand mixers, if they can be used, used with what kind of dough, and with what amount of dough is very model dependent.
From my own experience with a standard Siemens device (mymix 300W, specified as 0.5kg total weight in mixing bowl): recipes up to 500-600g flour will in practice work well (less for very heavy doughs). Making too wet doughs is not a good idea with that type of dough hook - since they have little working surface but high speed they will lose all "traction" on the dough if it is drippingly wet.
The advantage compared to hand kneading is that it is far easier to thoroughly incorporate an ingredient late in the kneading, and that you don't get the "kneading dough is nice, you get such clean hands from it" effect. Also, with some doughs these devices work very quick - minutes to a reasonably smooth dough.
Disadvantage is the more restricted hydration range, and more disruptive action (these hooks can saw a ball of dough in half if applied from the right angle).
Physical strength is needed to control mixer and bowl, so there is no clear advantage there compared to hand kneading.