undercoating as a bed liner?

Took my kei truck in to get some rust repair and asked for more info on getting a bedliner. They said they would use barrier bond which I looked up and it is labeled as an undercoating https://tcpglobal.com/collections/brand-barrier-bond/products/brb-uc34-kit-gun. Searching through this and other subs I can't seem to find a solid answer...is that a thing to use an undercoating as a bedliner? I was thinking something more in the lines of rhino liner, line-x, por15 type of product...