I used them a few times upto level 2 (only for available dates on very short notice, like within 2 weeks) and it seems to work (although you never know for sure without additional feedback from the guest). But doing the promotion yourself externally (on social media, websites) does it much better job. Maybe read this (very old) post: Direct marketing for your Airbnb
Thanks @Emiel1 . I will have a read over the link you sent me. I have no idea how to promote through FB or Social Media. Do you promote through your own FB/ Instagram or on a separate site? Love your feedback.
@Stephanie1933 You don't use promotions to get bookings. You use them to get eyes and click-throughs on your listing, which raises you in rankings, which results in non-discounted bookings.
Those unbooked days a few weeks away should remain priced consistent with what other guests have paid. Changing your listing description so your place goes up in search results as recently updated will get you more views and those dates will probably get booked.