I've always been a fan of smart home technology, be it internet accessible switches, smart radiator controls or wireless sensors collecting temperature and humidity data from my home.
The only problem with this stuff is that the commercial solutions are either cheap and dumb, smart and expensive or just pointless crap. An example for a 'dumb' device would be these 433mhz plugs, which can be hacked and connected to the internet, but dont provide any feedback whether they received the command or not.
Most of the smart home solutions you see in commercials belong to the second category: smart and expensive. Examples would be the Philips Hue light bulbs (RGB bulb: 45€), the EQ3 HomeMatic IP system (switchable socket: 40€) or the new Bosch Smart Home (switchable socket: 50€). In most cases these devices come with an easy to use software, can be controlled via internet using the manufacturers' cloud services and even include Amazon Alexa skills for voice control. However these systems can get ridiculously expensive. If one room has 2 lamps and one radiator, you would pay approximately 100-150€ per room to automate your house.
Then there would be the last category named "pointless crap". To these category you can count wifi-enabled sockets, bulbs and switches. At first these are tedious to set up since you need to connect every single switch to your wifi network. Furthermore these devices have a standby power consumption of about 1.5W to maintain their wifi connection. So every single switch will cost you about 13kWh (about 3-4€) a year. Other things that I can't recommend buying are imported smart home solutions from China like the Xiaomi system and no-name-brands picked up from discount- and hardware stores (unless they use the standard 433MHz system, see category one). You will likely have issues extending your system if the shop doesnt have compatible deviced stocked any more. Plus if you get Chinese stuff there might be problems with localization/translation of the software and you will need ugly adapters to use them with European or American plugs.