money mostly. It’s cheaper to do this than it is to build a whole ass new permanent building. Sometimes it’s also faster. My highschool (loooong time ago) was planning basically a rolling teardown of the entire campus to rebuild everything like 4X bigger, and to accommodate that they covered a parking lot with these things for the better part of a decade, as they had to wait for summer to do the major “not safe with kids around” construction every year.
money mostly. It’s cheaper to do this than it is to build a whole ass new permanent building. Sometimes it’s also faster. My highschool (loooong time ago) was planning basically a rolling teardown of the entire campus to rebuild everything like 4X bigger, and to accommodate that they covered a parking lot with these things for the better part of a decade, as they had to wait for summer to do the major “not safe with kids around” construction every year.