|You've got 4.5 watts. Check the power requirements for your devices. A 4.5 W fan isn't much of a fan. 4.5 W of LED light is bordering on the usable. A plain clock can easily run on 4.5 W, but if you are thinking of one with light and radio to wake you up to and animated display and so on, maybe it will break the power limit. Usually you can find the power consumption on some label.
And then: What you get without negotiation is five volts. If you want to adapt existing electronics, they may be built for two AA batteries, three volts, or for twelve volts. Some are for nine volts. So you will have to add some voltage regulator. Then you might consider adding a chip for USB power negotiation as well, and you will have the option for both higher voltage and higher effect.
I wouldn't have gone for USB as a low-voltage distribution system, though. Specifically: I am not going for it, I go for 12/24 V. I am in the process of stretching cables from the accumulators of my solar panels to sockets "all over the house". I go for far more robust plugs than USB-C; they will be XLR, probably 3-pin with ground, 12V and 24V. Before I start buying the sockets, I will again consider 5-pin, with a pin for 5V. The 12-to-5V converter will be right behind the socket, no 5V cabling, so maybe I rather put that converter outside the wall. I will put together various cables with XLR plugs for the wall side (usually the angled variant so it won't stick too much out), and various plugs / sockets in the other end: The common 12 VDC adapter plugs, the car cigarette lighter socket type etc. You can find most plug/socket types e.g. on Mouser.
At low voltage - definitely at 5V - the current for a given effect is high. The USB wires are thin. The losses are high. You cannot run long cables. That is why I added 24V alongside with 12V - actually, I've got 24V only from the accumulators to each floor, to a 24-to-12V converter. I am careful to minimize cable lengths: A "spine" along the middle wall through the house, fed from the middle. From the spine run "ribs" to the sockets, mostly on the center wall, or in a right angle out to a ceiling lamp. - Yet, I am using 4 sqmm cable for the spine, 2.5 sqmm for the ribs. I do not know the wire gauge used by USB-C, but it is a tiny fraction of this. For the cables, I might use thinner conductors; that depends on length and expected power consumption. Each rib will be protected by a fuse corresponding to the expected power drawn on that rib.
Note that the Wikipedia: USB-C[^] article states (in the Cables section): Cable length should be ≤2 m for Gen 1 or ≤1 m for Gen 2. This is usually good enough for equipment connected to the PC, but rather limiting if you intend to use it as a general power distribution system.
Bonus question: Why??
A couple reasons. We had a period of maybe 20 years with very few power outages - cables and transformers and whathaveyou up to modern standards. Then they started "optimizing", tuning the distribution for the absolute maximum utilization, and nowadays there are more or less zero safety margins. If an electrician sneezes at one power station, the fallout might ripple from one station to the next for twenty or thirty kilometers, maybe more. So the last few years, we have had a greatly increased number of power fallouts, the real cause far away, but the ripples are seemingly impossible to control. I do not want my house to get dark and communication to stop when this happens.
Second: In this country, you cannot do anything yourself on the 230VAC installation. You have to call an electrician for anything beyond replacing a broken fuse. For a 12VDC setup, you can put up a new lamp, or install a new outlet, yourself when you need it, saving at least a hundred Euro, maybe two hundred Euro.
Third: Adding computer control to a low voltage network can be done far more cheaply and easily, and in a far more compact way, than you can with a 230VAC network. And you can do it yourself.