Then it’s a useless system, though what’s it going to do for you?

If you’re concerned about living alone, and want cameras for security, first of all, you should have a comprehensive security system, and it should be professionally monitored, which means that there does need to be outside access .

The monitoring service will attempt to contact you, and then contact police or fire as appropriate.

alarm systems, generally have off, away, and home modes. In home mode indoor cameras should be disabled.

The main way that these cameras get hacked is that they arrive with well-known admin user/pass combinations and use uPNP to request port forwarding on your router. Search engines crawling the web find your camera so it becomes searchable on Google and Shodan which is when it becomes a problem.
Now someone has access to what is essentially a small linux server, often with well-known exploits, sitting inside your network.

Following some basic security steps ike changing the admin user/pass, disabling uPNP and blocking external traffic to/from your webcam will greatly reduce the risk.

The next risk comes from buying cameras that are designed to use an app as they’ll call home directly to enable you to connect without setting up port forwading or dynamic DNS. These ones are then at risk of your account and/or their home server being hacked and again gaining access to your camera.

I had multiple cameras indoors (nursery, lounge and kitchen) when our son was born as it allowed either of us to drop-in and say hi without having to disturb the other half e.g. when feeding or in the middle of play. These cameras were all standard IP cameras without fancy apps, on the same network as the rest of my devices but specifically blacklisted for external access in the firewall so only accessible via VPN.

Once he started nursery we took the cameras out of the lounge and his bedroom but left the one in the kitchen to keep an eye on the cooker and back door.