As with anything that isn’t totally self-contained, what else it works with is very important in making a purchase decision. Otherwise, you are locked into a single vendor and are at their mercy as to what other products they sell. There are three main, modern types of wireless networks found in smart home applications. These are WiFi, Z-Wave and Zigbee. As a user, you don’t need to know the technical details and differences; just understand that they don’t directly interoperate. A Z-Wave device, for example, cannot communicate to a device or smarthome hub that uses WiFi or Zigbee. Many hub are multinetwork–supporting two more network types directly. The Hubitat Elevation hub that I use, supports Z-Wave and Zigbee devices as well as a wired connection to a WiFi router.
WiFi is really designed for performance, each generation having much high throughput than the previous, and not for low data rate but extreme battery life applications. Your leak sensor, for example, will hopefully sit idle for years without signaling a water leak and if it does, it is a simple leak/no leak condition. Z-Wave and Zigbee were designed specifically for those battery-operated sensor conditions. For example, some WiFi smart-locks are rated at 1-2 months between battery changes as opposed to Z-Wave/Zigbee locks often rated at 1-3 years between battery changes.
And then there is Thread
It should not be surprising in technology that no company wants to give any competitor any advantage. So you will see several similar standards groups emerging and you will see companies hedging their bets, so to speak, by joining multiple, competing standards groups. And newer standards efforts can learn lessons from older standards or pivot to changing conditions. This standards posturing does not benefit consumers but it is the way technology develops. Or as the old saying goes, “the nice thing about standards is there are so many of them to choose from.” (Attributed to Andrew Tanenbaum but similar to a quote attributed to Grace Hopper.) And as someone working in computer networking since 1972 and wireless since 1975, I completely agree. Even though the Internet was developed for the slowest of networks and the least powerful of computers (just consider the situation of 1970’s technology), many engineers decide that the Internet is too complicated and invent something new and “better” (not invented here at its best).