Impolite? I've never heard of an expectation to pay someone for talking to you. Not saying there aren't examples of when it's a good idea, and I've done it before. Don't think anyone should be expected to pay for information, though.
Agreed. Things like directions and time of day are basic human interactions which we all reciprocate eventually. When I give directions (I live in NYC, happens a lot), I feel good about helping someone out, which is enough of a tip for me.
However, let's say you went to a theater performance, and one cast member was amazing and really stood out. Maybe the playbill has a donation QR next to each cast member. Micro-tipping in that case would be appropriate. Or maybe a little extra specifically for the cook at a restaurant, or the pool guy, or the plumber, or the car mechanic.