OKRs are effectively a quarterly negotiation to get alignment across teams so that large, complex, projects get done on time.
They create accountability and the ability to escalate up the chain when a team you have a dependency on isn't prioritizing what you need to unblock your project.
Generally, if you think OKRs are bullshit, it means they're being applied at a too granular level, or misapplied in an organization that doesn't require strong collaboration across team or org boundaries.
It "seems" easy and obvious when you're a leaf node how a team, org, company should be run and coordinated, but when you actually try and do it, and lead, it's nowhere near as easy as it seems.
OKRs, misapplied, suck. But there has to be some way to get large groups of people to align on specific targets. Effectively something like them have to exist.