You need a military in order to prevent other people from bombing your country. You absolutely do not need to bomb other people, and if fact if your goal is to not get bombed, not bombing other people might be your best option for a bunch of reasons[1]. If your goal is to systematically rob your population of wealth by dumping insane amounts of money into an otherwise mostly useless industry(you don't really need 12 carriers to defend your country for example, they are mostly useless for defense), bombing other people is a good option.
[1] not making additional enemies, not setting the precedent that it's ok to bomb people, not driving away allies, not undermining your narrative that you're a good guy and therefore attacking you is unjustifiable, etc. These are just off the top of my head.
[1] not making additional enemies, not setting the precedent that it's ok to bomb people, not driving away allies, not undermining your narrative that you're a good guy and therefore attacking you is unjustifiable, etc. These are just off the top of my head.