This is the matter of personal preference, but parks, libraries, schools, playgrounds, beautification projects, public transport, water quality, the list goes on. If nothing else, property tax reduction.

> Also, why having more infrastructure is automatically bad?

Don't think it's that absolute.

Think about tax dollars collected from a given square mile vs tax dollars spent on a given square mile. Suburbs tend to decrease the former and increase the latter, high-density projects tend to move the money in the opposite direction.