Personally, a 3D printer that has to be connected to a cloud would be a hard no. Even more so when that cloud is located in China without EU or US oversight.
I don't see why a 3D printer in particular would be a concern, unless you're prototyping stuff for a business and worried about proprietary commercial stuff getting out.
But I'm amazed that people in general are willing to connect their systems -- 3D printer or anything else -- to an outside provider's service. It has a considerable number of drawbacks.
It punches a hole in what is normally the front line for home computer security, the firewall/NAT device. Most setups default to not allowing inbound connections. Now you've got some device that is opening connections outwards and could talk to other systems on your network.
It permits the manufacturer of the device to change the terms on which I can use the device. Maybe down the line the manufacturer of your smart TV -- who is not getting any revenue from you after the initial sale of the device -- decides to start inserting ads, say. This sort of thing has been done before. I want the manufacturer's interests to be aligned with mine. Before the product is sold, they have to convince me to buy the thing. Afterwards, those interests could diverge. I don't want the manufacturer to be able to alter the terms on which the product I bought may be used if our interests have diverged.
Even if you want to trust the manufacturer's intent, can they secure their own system against people with more malicious aims? If someone can break into that, they can affect all of the customers, which may make it a tempting target. Russian intelligence attacked Viasat satellite modems, using an exploit that they'd clearly found earlier, when Russia invaded Ukraine to try to disrupt Ukrainian communications. They pushed a firmware update to brick modems. They didn't even just impact systems in Ukraine, but also some outside, like a German offshore wind farm's control system.
If any functionality depends on that manufacturer staying in business and being willing to keep paying for the operating costs, that seems fragile. Many companies do go out of business or decide that the costs of operating a service aren't worth it.
Just being able to track someone's moves across IP adresses has some value; reselling that information helps deanonymize people. Could happen down the line if a company is acquired by a larger company that data-mines its logs.
If you lose Internet connectivity for any reason, you lose local functionality. Home automation stuff is a particularly egregious example -- you don't want your light switches or climate control to stop working if you don't have Internet connectivity to somene's cloud service. But it's true for any number of things.