It raises the value of the land (gives SLA and real estate 'stakeholders' an erection), and creates business for developers and contractors. That's the name of the game.
Another sneaky tactic of theirs: they say
not enough children to enrol, so some schools have to be merged or closed. For example, School A and School B merge, School A gets enbloc'ed and the school building gets upsized to accomodate more students. School B gets demolished... and you should already know what that piece of land gets used for.