I was just burned badly--Smart Pricing is horribly broken and illogical. I activated it to try. It overrode ALL dates INCLUDING dates I had already assigned a custom price to--very important special event dates.
Sounds similar to what @Grace339 mentioned.
I knew it would dynamically adjust "regular" dates (that's the whole point) but, no, it also wiped out CUSTOM-priced dates (dates that already had a custom price set).
Within hours, I had a booking request from a guest pouncing on an opportunity to get the house at a FRACTION of its worth on an NCAA football weekend, where "Smart" Pricing had destroyed my custom price and set the house at pennies (relatively). I had to decline and explain that Airbnb had messed it up, badly.
Smart Pricing...isn't, apparently.