There's an episode in the Acquiring Mind podcast that talked about this strategy, and it seemed pretty effective. As with any marketing strategy, it will take some time, consistency, and system to get to a funnel of leads.

It also depends on the type of businesses and demographics you are targeting. Owners at retirement age that run blue-collar based businesses are going to be in this demographic.

They can be quite effective depending on the strategy employed, audience, message, call to action, content etc.

with digital costing more and more over the years then snail mail may seem more attractive

what if instead of an abandon cart email you had a personalized mail with a code for you to use? Could be effective depending on use case