I have a technical routine that I go through daily. Is it fun? No. Does it work? I believe so. Why do I do it? Because my piano teacher whom I trust wholeheartedly told me to do them.
The routine takes me about an hour, maybe an hour and fifteen minutes, but that is because I'm still at low tempos. I start with a stretching exercise from Adele Marcus (who was my teacher's teacher), then I do a Rachmaninov stretch for four keys. Then, I do exercise 2 of the Dohnanyi set, then 3 and 4 on one day, 5 and 6 on the next, and number 8 changing key daily. Then I do five of the first 31 exercises of Hanon, switching every day. Then I do my scales, three keys a day, octave apart, third apart, sixth apart, tenth apart, natural minor, harmonic minor, melodic minor, and arpeggios, major and minor, dominant seventh and diminished seventh. The question to me is not whether or not you do your exercises, it's how you do them. During the Dohnanyi and the Hanon, the large focus is relaxing the hand, making sure the knuckles don't collapse, and playing with the tip of the thumb instead of the side. Scales and arpeggios build upon those, adding guiding the hand with the elbow and making sure the elbow doesn't "flip" when the thumb passes. So I mostly concentrate during technical exercises on ensuring a correct coordination of the body for playing. I was a member of the no-exercise camp until my first year of college. I find, personally, that the technical improvements I've made have increased my sight-reading skills and make the motions feel more natural when I apply them to real repertoire. I also should note that I don't do any of these exercises without a metronome. The metronome helps me keep everything even, which means I can reach higher speeds without stumbling.
Finally, please note that this hour on technique is one out of the four I am expected to practice a day. My current rep includes Bach's Prelude and Fugue in A minor, Book II, Beethoven's Sonata No. 9 in E major, Ravel's Valses Nobles et Sentimales, and Robert Muczynski's Six Preludes Op. 6, so I spend plenty, plenty of time on music, and technical work is only a portion of my practice. Do I believe all of those exercises are necessary. For me, yes, for all, no. I do believe scales and arpeggios are necessary, though. You may not see the need, but all the work I do on coordination and fingerwork during scales and arpeggios pays off for me in actual pieces. It is not about the fingering, it's about how you use your fingers in general, as well as your arms and your whole body. I find in my sightreading as soon as I find a scale or arpeggio I can play it with ease, and they are all over the place.