In the last two centuries, interest has moved away from electricity towards lesser known expressions of energy. Leaps in mathematics and quantum mechanics have channeled interest into vibrations, higher dimensions, dark matter, higs bosons, dualism etc. These are getting matched up with surviving mystical and alchemical formulas. We mystics continue looking for the underlying explanation. Nowadays we've scientifically run up against a wall. It is the vibrational-reality wall -- the mystery of our time. At very small sizes we are unable to measure both position and location of any particle, although we can determine either one individually. Why? Because of vibrations!
Certain quantum effects can only be modeled using 4th dimensional mathematics. Vibrations become of interest when you imagine that there are 4 dimensions instead of three, although I'm not suggesting objects as we think of them could exist in 4 dimensions. It does make me wonder if they could. Our world, with its three dimensions, is perceived by us through the means of linear-time. Our eyes move side to side, up and down, and our heads move forward and backward. These are three dimensions measured by a single clock. Measurement is the time it takes for our eyes, heads, hands, bodies etc to move through a space. We cannot perceive a fourth dimension object, because it cannot be experienced with a single clock. It has be seen through means of a time-squared function. We are unable to perceive time-squared, so quantum effects appear to us as random unpredictable vibrations in linear time. The best way we know of accounting for them is to study them statistically. (Incidentally there is a fantastic series of videos that introduce the concepts of 4th dimensional math and complex numbers at
Dimensions They are very entertaining and informative.)
Energy sources are always of interest, because mystics are always looking for an explanation for things. Sometimes our interest is spiritual and psychological, sometimes alchemical. Sometimes its just for magic shows. Just as you said, there are shysters who sell fake gimmicks. For whatever reason, energy is where its at, man. In the 19th century, we were fascinated with electricity. Before that it was light, or fire, or cold & heat, myst, acids, sound, numerology, musics, critters, and whatever else was attributed to the universes' underlying controls and expressions. Is New Age anything new?