Working on a 32MLOC project, text search is still the quickest way to find a hook that gets you to the deeper investigation. From there, finding definitions/usage definitely matters.
You can maybe skip the greppability if the code base is of a size that you can hold the rough shape and names in your head, but a "get a list of things that sound like they might be related to my problem" operation is still extremely helpful. And it's also worth keeping in mind that greppability matters to onboarding.
Does that mean it should be an overriding design concern? No. But it does mean that if it's cheap to build greppable, you probably should, because it's a net positive.
You can maybe skip the greppability if the code base is of a size that you can hold the rough shape and names in your head, but a "get a list of things that sound like they might be related to my problem" operation is still extremely helpful. And it's also worth keeping in mind that greppability matters to onboarding.
Does that mean it should be an overriding design concern? No. But it does mean that if it's cheap to build greppable, you probably should, because it's a net positive.