We’ll go over two such ways.
Web components provide a lot. They also introduce many questions, and each one of those questions can be answered differently depending on perspective, time constraints, and development attitude. Web components, at their base, provide a layer of abstraction and push an API touchpoint to the HTML itself. This is already a win, and for a lot of people, that is the primary appeal.
At the other extreme, there are people who see web components as an opportunity to implement the next generation of building blocks that will compose the Web of the future. There are already implementations of spec proposals floating around on the Internet, and it’s not a stretch to believe that independently developed individual web components may end up as official elements existing in the actual HTML spec one day.
Neither attitude is necessarily better than the other; they are just different and excel in their own ways. With those two attitudes, though, comes a choice of tools and implementations. Do you reuse what you know, love, and are familiar with to get a job done? Or do you toss the past aside, and implement these building blocks from the ground up?
Why port anything to Polymer, ...