I have accumulated so much smart-stuff fatigue, I can't stand anything branded as "smart". This means, as you point out, 1) any outage in the chain between me and the vendor's app shuts everything down for me, 2) stuff behaves inconsistently all the time. (e.g. Bluetooth speakers with a smartphone/tablet player app -- every other time something goes wrong: the app frozen completely because search autocomplete lost packets; you can't find the damn playlist buried in a sea of features; another your device wakes up and steals the bluetooth speakers.)
Regarding the electric switches, I was fond of bypass switches (where you can turn on/off by flipping any of the switches connected to a lamp) and made a lot of them in my apartments. Turned out not all of them were needed. I didn't need much control at home, e.g. I don't need to control the lighting above the kitchen desk when I'm not in front of it.
Wifi switches allow a lot of freedom in positioning and re-positioning them, but they escalate everything to the unreliable realm of IP/internet devices. I'd probably vote for a controller on a lamp, and switches not actually inerrupting 230V~, but be connected with a thin and flat 12V= bus, and just signalling, and hence be easy to put under wallpapers. (5V= would be hard to send further than 3 metres.)
Modern smart switches are pretty small (most of them are designed to fit into wall sockets behind plugs/light switches).
I personally think relays are a much more reliable than solid state switches and are very unlikely to fail in a dangerous way, and fully interupt the circuit, but they do have a 'click' some people dislike, and have a lifetime of 100k-ish switches, so for an application where you keep switching rapidly (e.g. not light switches), this might be a problem.
Ikea used Thread and Zigbee which are not Wifi, they use a mesh network and don't suffer from saturation the way Wifi does, in fact adding more devices tends to make the network more reliable since devices can route around failing or congested nodes.
I've had good experience with them in practice, but do be mindful that they share the 2.4GHz band with Wifi so in an apt building, you might run into radio channel congestion.
Personally I use smart home stuff for controlling heating devices and a few other key items, I don't think it makes sense to make every light switch smart, but technically people have done so and it tends to work all right.
Regarding the electric switches, I was fond of bypass switches (where you can turn on/off by flipping any of the switches connected to a lamp) and made a lot of them in my apartments. Turned out not all of them were needed. I didn't need much control at home, e.g. I don't need to control the lighting above the kitchen desk when I'm not in front of it.
Wifi switches allow a lot of freedom in positioning and re-positioning them, but they escalate everything to the unreliable realm of IP/internet devices. I'd probably vote for a controller on a lamp, and switches not actually inerrupting 230V~, but be connected with a thin and flat 12V= bus, and just signalling, and hence be easy to put under wallpapers. (5V= would be hard to send further than 3 metres.)