From the clip: “Many audio enthusiasts still prefer tube sound, which they find warmer, richer and more natural.”
Audiophiles may agree or disagree on the relative merits of tube vs solid state amplification. Some say they prefer the sound produced from tube amplifiers on the grounds that it is more natural and satisfying than the sound from transistor amplifiers. Otherwise this preference or difference is far too generalized or even vague without taking amplifier designs into consideration, and there are many. Certainly these audible differences are due to distortion types: harmonic, distribution, level and many other factors. (Wikipedia)
Whatever your opinion, tubes are here to stay.