Lenovo's 'Link' solution for an Android Phone is not even close to what Continuum can do via either Microsoft supplied docks (both Continuum or Miracast) or third party vendor docks (both Continuum or Miracast)
1. Whether you use a Continuum dock or Miracast capable device with latest Windows 10 mobile hardware, you see full screen resolution on your display output. i.e true scaling of the smartphone view along with more and more apps also getting updated to go full screen in that mode. With this wired adapter, it's not full screen.
2. You can Miracast/Continuum your Smartphone 100% wirelessly to the display output depending on which brand adapter you use. They cost as low NZ$50 brand new and available in NZ. Most new smart TV, projectors, streaming devices like Roku have built in support for Miracast so need to even buy the adapter.
3. You have been able to duplicate your Windows Phone 8.1 and below running OS smartphones for a long time for free using your standard micro USB to USB cable supplied in box for free without buying any additional hardware and showing this same cut resolution of the screen for a while which also includes doing it via Miracast. I have been showing photos and videos to my family on my Roku via my Nokia Lumia 1520 for last 12 months. All free without the use of buying any extra adapters etc.
Miracast and Continuum on Windows 10 Mobile is much more powerful in terms of features and functionality and works with a wide load of adapters, TV, Projectors and streaming devices that you prob already have in your household.
What I don't get about Continuum is, in order for it to be useful, you need the dock, cable, screen and keyboard to make it work. Well, if you have all that kit, you're going to have a lightweight Surface Pro or similar as well, so you are unlikely to replace your full Windows 10 PC experience with a cut-down version on your phone. You'll just boot up your Surface Pro in preference.
What I do get with Lenovo Link is the ability to join your smartphone into the PC experience - a much more likely scenario than seeking to replace your PC with a cut-down operating system on your phone. Where I see Lenovo Link being really useful is that when working on a PC at work or home, I can link my android environment directly with Windows 10 and interact with both seamlessly from the one device.