I figure if there's value to it, grids will do it.
For example, a large varregion could be great for sailing. Or airplanes. Or space battles. Or for large-scale roleplaying campaigns with groups of explorers marching across vast deserts and mountains -- things you cannot currently do in Second Life except at great expenses.
This is one of the unique affordances of OpenSim -- to have a large swathes of land in which to do stuff. Why not take advantage of it, and promote it?
Not every grid can afford to provide this much land to its residents. Even a varregion still requires server resources. For some grids, the money would be better spent on marketing, or support, or content, or upgrading the hardware on existing regions. But if a grid can afford it, and it benefits its residents, and benefits the grid -- I'm all for it.