Nintendo Switch is a hybrid console, part handheld and part home console. In order to use the handheld as a home console, you will need to attach it with the dock. However, if you are planning to attach docks to multiple TVs then you will have to give up $89.99 for each as 3rd party Nintendo Switch dock is very unlikely.
Nintendo has patented the logic controller behind displaying the Switch itself to a TV and did it so quickly that it is very unlikely that Nintendo would license the technology to third party manufacturers like HORI or Nyko and obviously you will have to play $89.99 to get a new one from Nintendo.
Also, a number of copyright and patent documents have been leaked that showcase that the dock for Nintendo Switch could have been very different in design than how it is now. Apparently, Nintendo wanted to cover as many bases as they could before they started production.
Nintendo Switch is now available worldwide and is priced at $299.99 in the US.