Not using schema binding seems like turning off compiler warnings - you don't find out you broke something until runtime.
The benefit is that schema bound objects protects the database from accidental or deliberate changes that could break dependencies later.
The cost of the protection is that maintenance is more complicated because schema bound objects sometimes require altering multiple objects in a particular order to achieve what would otherwise be a simple localized change. This cost is relative since without the schema binding a change could silently break something that requires more maintenance later.
I think the benefit outweighs the cost, especially for established databases that aren't changing much (less changes so less maintenance) or where you don't know the dependencies (less familiar so more risk).
Are there situations where schema binding shouldn't be used?