Maybe for now, but problems will arise sooner or later when the products get not longer supported or discontinued. Of those things you listed there's a high possibility most of those won't work anymore in 10 years. And you normally build houses for longer timespans and don't want to change basic controls (lighting, heating) short intervals. I wouldn't invest a large amount in Smartthings or Google products for those reasons. The Z-Wave might be one of the more reasonable things, as the protocol and device classes are standardized and most devices are interoperable. But with the so much fragmented home automation domain (there's KNX, Z-Wave, Z-Wave Plus, Enocean, Zigbee HA, Zigbee LL, and dozens of others) it's even questionable how long classic Z-Wave will survive.