Asklemmy

Most smart home devices are actually not that smart. They are simply a switch with wifi, which logs in to your local wifi and shouts "HERE I AM, I HAVE TWO MODES, YOU CANSWITCH BETWEEN THOSE" into the ether.

Reasons to have a hub are:

1. Not having to open the website of every single device or send a command from the command line if you want to use it, but rather have one place which registerss all devices and bundles them up to serve you in a nice web interface or app.

2. Have more advanced/intercinnected functions (not only: send "up" to the blinds device but send "up" to the blinds device, if the time device says its later then 8:00 and the daylight sensor device senses dalight.

3. Some hubs have security features, like claiming the device and establishing a password, so not everyone in you WiFi can do everything.

4. Good ones act like a protective layer from you to the outside internet (esps and most smart home devices are simple devices, which are rather unsecure and where you don't know which code is running (your Chinese security camera might not only send pictures to you but also to China, and you would not knowbif its connected to the internet directly). So you can only allow connections to the hub, and if you have an open source hub like HomeAssistant, you could be rather certain stuff like this will not happen as easily.

5. Do all the heavy lifting with more CPU power (user and password login, updates, scripts, voice recognition if you want stuff like this, keeping date and time recently updated, merge (in the case of HomeAssitant) different protocols (like iqtt, phillipsHUE, ZigBee, etc. Pp.) Into one coherent system.

Some other things also, and that being said: it is literally the device controlling your entire house and privacy, so get one you trust, preferable an open source one where you don't have to accept agbs to give up all rights to Samsung or so.