The process of optimization is to define the best solutions which give the maximum performance and effectiveness. If one thinks of UX as pure visuals, fancy interactions, and the latest front-end technologies then you need to understand that there is a lot more to it.
UX is all about users and how you design things to make sure it is effectively used by the end users. If your design is not compelling enough to drive a user towards the desired task then the UX is a failure. If the experience is bad for one user then it will have repercussions on the overall system.
So, better UX means a better product. You can always achieve this with proper process of personas, A/B testing, cognitive walkthroughs, testing with users and repeating the process at each level till you get substantial data and values from end users.