>I also do not understand why "Closed-loop" terminology is implying that this system is something new or distinct as all geothermal systems to my knowledge use closed loop systems to prevent environmental damage

Large-scale geothermal systems attempted up to now have generally been of the the type where you frack deep underground rock, then dig two wells into the fracked rock field, pump cool water into one and let it heat as it percolates through, then pump it back out the other.

This as you mention carries the potential for environmental damage, but has been seen as necessary to overcome the problem of rock's slow thermal recharge rate.

The linked paper suggests the rock thermal recharge problem can be overcome by digging not one but several horizontal pipes connecting the two deep vertical wells.