Yooka-Laylee was one of the most successful games on Kickstarter. However some games that go through Kickstarter tend to only have digital releases at launch, this is mainly due to the manufacturing costs that are need to make a retail release.
However <a href=http://www.playtonicgames.com/thinking-inside-box/">in a development update</a> on Playtonic's site, the developer said the game will be offered in both digital and retail at launch. The studio is also working on a way for backers of the digital to upgrade to the physical version, if they so wish.
Yooka-Laylee is out Q1 2017 for PC, PlayStation 4, Xbox One and Wii U.