The Vero hardware, like the Pi, does not support software power off - after a Shutdown the OS will be shut down (all processes terminated and file system changes synced) but the hardware will still be on drawing power and outputting an HDMI signal. It is then safe to disconnect the power.
Sam has suggested that a pseudo-suspend mode may be possible in the future, but the device will in reality still be on but with minimal power consumption and probably no HDMI signal. (It’s not a true suspend mode like hibernate to disk on a PC)
Total power usage of the vero when idle is only about 2.5 watts and 3.5 watts under full CPU load. SD card life span is affected mainly by writes, when sitting idle there will not be many writes unless you have addons configured to automatically do library scans or other background work, but even then modern SD cards with wear levelling (those with good 4K random write performance) will last a very long time.
I’m yet to have any of my SD cards give any issues and I use them heavily in the course of development and testing by frequently reinstalling and even doing multiple hour long compiles of Kodi etc directly on the SD cards so SD card life really isn’t an issue.