Majority of the people would say that "XF Lens" is the main attraction of the X-mount lens. The lineup consists of large diameter prime lenses and F2.8 constant zoom lens.
But do not miss out on the two renewed XC lenses!
Making a lens lightweight and compact is a major constraint for the designer, but it would be a major advantage for the users. The only concern is how well will the lens perform with the constraint. If the performance meets the photographers' needs, then it would definitely be the best lens in one's arsenal.
For example, there is only XC16-50mmF3.5-5.6 OIS II aside from the XF16-55mmF2.8 that covers the mid-telephoto range of 24mm to 75mm equivalent. And it only weighs 195g! Only the XF18mmF2, XF27mmF2.8, and XF35mmF1.4 weigh lighter than the XC16-50mm lens.
The lens can also get as close as 15cm to the subject. This is closest you can get among all the lenses!
By realizing the unique characteristics of the small sized lens, it can outperform other lenses in certain areas.
X-mount lenses are lenses without a compromise.