There is already some AirTag chat here, including a surprise early delivery from Facebook marketplace which may or may not be real: https://community.monzo.com/t/apple-april-event/
As this is in the main Monzo category and Travelling with Monzo subcategory I’m not sure how fitting it is
But to answer the question, yes, I’ll be getting one when JL start selling them because I’m a sucker for all things new and shiny and Apple. I think I’ll pop it on my keys which I never once lost. Maybe now? 
I don’t quite know how they’d work with wallets – mine is a minimal slim cardholder wallet, but even with bulkier ones, do you attach one or put it inside? Doesn’t seem like an elegant solution