Cable company allows a limited number of connections to the internet. With multiple smart plugs and lights, these add up. Can you use a hub/switch for one connection to the internet then have all the smart devices connect to the hub instead of a direct internet connection? Then instead of 10+ smart devices connected to the internet you'll have the one hub. Make sense? Can that be done?
The NATing that routers perform is what keeps you safe from attacks launched on the public network (internet). Your router blocks (discard) all incoming data that it is not expecting. If you visit a site, then your router expects to get a reply from that site, and allows it. Otherwise, your router tosses it. It keeps predators from even knowing that your router exists. And if an attacker cannot penetrate your router, then they have zero access to your devices that are plugged into your router (plugged in includes wireless connections, too). This is why attackers try so hard to get you to click on things. If you do so, then you told your router that it has permission to allow a response to come back to you.
