Technically it does have push button start. You can start it remotely with the keyfob or with the Chevy app on your phone. Really useful when you want to warm the truck up when you are in your hotel room and your truck is parked outside. You just need to put the key in in order to put the transmission into drive. Personally I thought not having push button start was more of a PRO than a CON... one less feature to break. Who really needs it anyways.
I have a 2019 ZR2 with remote start. It came standard. At the very end of the video, look at the FOB. Press and hold the top button(above lock/unlock) for a few seconds and it'll start up!