I really like having the Nyon on my Cannondale Topstone Neo Carbon3. For me having custom ride modes, multiple custom screens with deep data and turn by turn directions, all without having to use my phone, makes Nyon worthwhile.
The Cannondale came with a Purion, so I had to have the shop run a new cable down to the motor. It is so much better than the Purion and a big improvement on the Kiox.
I have the older Nyon on my Trek Allant 9.9s. That bike came with the smart phone hub, which I would never have on a bike.
If you just want basic controls and don't care about complete ride data, customizing ride modes and a good record of your rides, don't bother with the Nyon.