It will always be up to people and their preferences. BeWelcome is after CouchSurfing the largest hospex platform so its understandable that for many people who are not willing to pay CS fees BW would be their number one choice. I am on all popular hospex platforms, BW, Trustroots and Couchers. They all are free so I always suggest people to join all of them and see which one suits you best. Couchers in my area currently offers more active hosts than BeWelcome or Trustroots so depending on the city, you might have actually a better luck with Couchers than with other hospex platforms.
I especially like Couchers for the reasons you mentioned: Clean, simple and nice website.
A good reason to tell your people in order to join could be that the website is rapidly growing. I think there is a 13 year gap between BeWelcome and Couchers and to me Couchers is already more user friendly and better looking platform.
FAQ explanation is pretty clear but here is a different statement made on social media by one of Couchers co-founders about it: “While we understand your point that the couch-surfing community should come together and work on existing projects (such as BeWelcome and TrustRoots), there are many of us out there that didn’t find these platforms a right fit for our needs. That is not to say we think these platforms are inherently bad, they are simply suited for a different niche. There is space for everyone, and health on one platform will benefit the others!”