The energies themselves aren’t that high, the problem is that the energy densities are high - the Planck mass, for example, which is usually taken as the highest possible energy in particle physics beyond which we have to take gravity into account, is equivalent to a mere 21 μg.
However, ‘practical’ uses of these physics are not immediately obvious in the way special relativity is necessary to get decent GPS[0]. Nevertheless, both the engineering advances _and_ the mathematical tools invented during such research prove very useful time and time again - methodology from String Theory, for example, is used in trying to find dynamical descriptions of superconductors, which, if found, will affect daily life strongly (hopefully).
The key point to keep in mind here is that predictions about the future are rather hard and we have no idea what weird things people come up with in twenty or thirty years time, let alone a hundred years. Or could you have predicted the global cat picture viewing machine mentioned next door in 1913?
[0] And to understand why more than 3 to 4 GHz are rather impractical if you want to keep the CPU and RAM physically separated, btw.