Since radio systems are not automation, I do not accept that here either. I also automated with Homematic myself (formerly in an apartment, now in an existing property). Unfortunately, currently only power and heating, since there are no electric roller shutters installed, but that will come later. By the way, the app control was added last. However, it is very convenient to see where the light is still on, who has called, whether mail has arrived, what the weather is like (automatic irrigation is coming). Especially when the house is often empty, it gives a good feeling, and absence control is also quite nice. With over 80 components, my radio system has so far been very stable. Occasionally a window sensor is unreachable, but that happens maybe twice a year. The central unit has crashed for me 3 times so far, and always during programming. In operation, the thing has been running absolutely flawlessly for 4 years, and most devices are connected via direct links. That means the automation programs would of course not work without the running central unit, but all functions are still operational via the switches, or the heating control is anyway stored in the thermostats. The only disadvantage is the use of batteries (thermostats, radio switches, window sensors). Even though they all last at least 2 years, that is still somewhat of an eyesore to me. Unfortunately, KNX cannot really be retrofitted, otherwise I would choose such a solution. Advantage of radio: If today I want a switch at any random place, I just stick it there. In addition, I can make every socket switchable or dimmable by means of a plug.
On automation: Of course, no one really needs it. Just like an induction stove, electric roller shutters, a floor-to-ceiling shower, expensive washbasins, and televisions in the bedroom. Nevertheless, very many people have it today because it is simply practical. I can also wash myself in an 80x80cm shower tray with a shower curtain without loss of quality (I get just as clean). Many would now say that this is not possible in a new building. It is similar with automation solutions. Clearly, 90% of it is pure comfort and it also costs money. My thermostats will take years to amortize themselves halfway. Even if they never do, the comfort gain would still be there. On weekends the rooms are heated differently than during the week (okay, in a low-energy house rather secondary). The stair light is switched by motion detector. At night, it is also at a different brightness than during the day. When guests are there, the guest bathroom and guest room are heated, the night lighting is on, and a temporary Wi-Fi key is generated. When I come home, I can see how much it rained during the day, who called, when the doorbell rang, what the weather will be like in the next few hours, and what is still on the calendar today.
If you want, depending on the time of day, season, person, etc., you can then start various things upon arrival home (radio on, lights on, blinds up, ...). But so far I have not needed that. The fact that a red light blinks on every floor when the washing machine is finished, however, has become a favorite of my wife. That is just a small thing, of course you can do without it, but it brings a significant gain in comfort. Especially if you are as forgetful as I am. You sometimes forget to retract the awning, leave the light on in the basement or the garage door open. That now regulates itself, or I can switch it remotely via VPN if necessary. At home, nothing is actually switched via smartphone, but only via the classic light switches and push buttons, or via the TV remote control. Here, with the press of a button, all devices can be started, blinds and lights can be switched, and that with a totally simple remote control that any child can operate intuitively. Previously, my wife was not able to play a DVD because she had to press the right buttons on the TV, AVR, HDMI switch, and BD player.