The signifigance is that a guided shell is like 10k while a missile is easily 1 mil. Thats 100 shell hits for the price of 1 missile hit. The economic dimension is what makes it strategically significant.
Guided rocket artillery should not cost that much, and a guided shell is unlikely to be quite that cheap and it's likely to have a far smaller payload.
More importantly, the size of tube artillery needed to launch a projectile at such distances means an artillery piece like that would be highly immobile, vulnerable, and difficult to logistically support.
There's a reason why these concepts get proposed every few decades but military forces just go back to long range rocket artillery or missile systems.
Unless there is some sort of new technologies that changes the equation in favour of large tube artillery pieces, the matter is not really worth discussing.