Does that mean "Intimidate" is kind of a universal 'apply Disadvantage to target' ability? Doesn't that just make it a zero-cost Fear spell? Can PCs do that to NPCs?
It's a potential option, but one with lots of fairly obvious consequences if you think about it. First of all, you have to succeed. And regardless of success, people really don't respond well to intimidation tactics. So maybe the person lets you pass this time, or runs away in fear or whatever, but you can bet they'll be looking for payback later on.
More importantly, as GM, i have no problem with my NPCs running in fear or cowering or even just giving up information after such a check, because they aren't Heroes. They're just NPCs. But Heroes who rely on intimidation because it's the easiest path aren't really deserving of the title, and that will get reflected as much as the story progresses. I'm a big advocate for player choices always having consequences -- often bad, and especially when the choice was the easy path.