Is it absolutely necessary to have a base/gateway? This Verge article[0] seems to imply not, but it's not at all clear to me what I lose.
If I just want a smart switch that controls a smart light, can I do that without a hub? Can I use my phone to control that light/switch in a pinch? I'm not averse to spending $100 or whatever, but it's just more _stuff_ that I'd rather not think about.
It's not strictly necessary to have separate a hub/controller, no: After all, a Matter controller is just a small computer-widget that sits on a network and talks with IP packets.
A pocket supercomputer, such as an iPhone, theoretically works just as well: It's a small computer-widget that sits on a network, right? It just happens to run on batteries and be carried around in your pocket.
It's just software at that point.
At the end of the day: The Matter devices are paired with the controller, similar to how Bluetooth devices are also typically paired with a main brain-box. (Except: A Matter device can be paired with many controllers concurrently, whereas a lot of Bluetooth devices can only be paired with one at a time.)
The network connection doesn't have to be permanent: It can work when controller is present on the network, and it will [perhaps obviously] cease to work when the controller is absent.
So if Apple has software that runs within an iPhone and acts as a Matter controller, then: Sure, no additional hardware is needed to wiggle the state of a Matter light bulb using your iPhone.
(And if that kind of local control is all you ever care about for controlling stuff then... that's good enough.)
If I just want a smart switch that controls a smart light, can I do that without a hub? Can I use my phone to control that light/switch in a pinch? I'm not averse to spending $100 or whatever, but it's just more _stuff_ that I'd rather not think about.
[0] "Apple now lets you add Matter devices to Apple Home without a hub" https://www.theverge.com/2024/9/18/24246581/ios18-matter-sma...