"The study of scales will solve a greater number of technical problems in a shorter amount of time than the study of any other technical exercise." Andre Segovia...and who am I to argue? The problem for instruction of scales is the unimaginative ways they are presented to students.

I've never, honestly, lost a student due to scales. I insist on them as a part of the warm-up regime. Every lesson starts with at least a couple (chromatic, majors, minors, pentatonics, and whatever) which takes but a minute or two, and very often I will instruct a student to play the scale in the key of the piece they are to play next, in order to acclimate themselves to the sound and feel of the key. Making ascending and descending exercises, rising and falling by intervals within a scale, makes them good fingering and ear training (and head understanding). They are the foundation of improvisation (jamming sounds better to some students), composition, and playing by ear. They are also good for finger discipline, interval recognition by sound, sight, and feel, fretboard memorization, and they are a good vehicle for practicing articulation devices like hammer-ons, pull-offs, slides, etc.

Naturally, your mileage may vary.

Peace, Mooh.