It doesn't look like the $250,000 goal will be reached to get zigbee but if you have the ability to add it you may get more customers who want to leave SmartThings.
Here are some sample posts regarding the desire for Zigbee
Thanks Ron!Your feedback is valuable to us. We have done a rearrangement of our stretch goalsbut we will have a look at integrating Zigbee from the start. A problem is thatthis integration can delay the product. I will inform you here of how we willproceed.
I totally agree with @ron Zigbee HA support is important to Many users, Not just Smarthings, But also Vera, Wink, Iris, and Staples Connect All include this functionality.
I hope you reconsider this decision.
If you don´t support Zigbee from the start you might add support for some different usb-modules that you can buy quite cheap on Ebay. Or/and sell your own.