As a student I found these exercises useful for building finger strength and independence. My teacher at that time took care to make sure my wrist was loose while I played them. Tendonitis/CTS etc. can result if these and similar exercises (Pischna, Herz and others) are played with a stiff wrist, keeping a given finger or fingers still while the others play is difficult. IMO these exercises should practiced slowly for the most part, with complete relaxation. Otherwise the bad things mentioned above could happen. I do not stress this sort of exercise in my own teaching, in fact I am on the verge of dispensing with the whole exercise/ drill approach (except for scales and arpeggios, double note exercises etc ) entirely, except for my yuonger students.