Why spend the limited internal energy of the Earth's core while the much less limited energy of our star, which is conveniently delivered daily to the surface, where it's easy to harvest?
I can understand geothermal energy in very high latitudes, like they do in Greenland, where Sun energy is scarce, and lava is close to the surface. On most of the earth, geothermal energy is much harder to get than solar.
Geothermal goes 24/7. Also don't underestimate winter even in more moderate climates like northern or even central Europe. Sure you'll get some sun, but it's limited to maybe 9 hours and rainy and overcast.
Are we already capable of harnessing enough to power anything actually serious and industrial, rather than a small household with some consumer electronics and lightbulbs somewhere like California, where heating isn't even an issue?
Easily accessible geothermal sources are relatively rare (unless you are willing to drill 10+ km as the article suggests), and picking energy from under your feet may have consequences for the land above, see e.g. [1].
I can understand geothermal energy in very high latitudes, like they do in Greenland, where Sun energy is scarce, and lava is close to the surface. On most of the earth, geothermal energy is much harder to get than solar.