With solid developers it can be pulled off with a fair bit of success. However there is a LOT of work that needs to put in order to make a quality web-app have

With solid developers it can be pulled off with a fair bit of success. However there is a LOT of work that needs to put in order to make a quality web-app have a good experience on all devices, it's not as simple as throwing the url to your web-app into a native container and hoping for the best. But like I've said it is possible. I've seen web solutions put into a native situation with performance that is nearly indistinguishable from a native experience. But having a chance to sit down with the developers there was a lot of work that they needed to be put in to get the web component to that level on mobile devices. There are reasons that people may want to choose using a web solution for their native product (ie over the air updates, extremely good web developer but lacking quality native developers, distribution of embedded apps without needed to go through the associated app store ect.) but if the reason is it's easier and takes less time, I'm sorry to say that that is not the case if your looking at providing a quality product.