They are most often used as short-haul taxis and may be souped-up or customized by their owner/driver. Young dudes can install sound systems that rock the foundations of nearby buildings. Nowadays, in Sri Lanka, two-stroke models are no longer allowed. However, one company does make diesel models.
I don't know who thought of using one as a promotional vehicle, so to speak. It's missing its roof and doesn't move much. Yet, it does now carry products on sale. This one is in our closest Keells Supermarket in Minuwangoda. It's been there for years, but I only thought to snap a photo today.