Tailscale funnels allow people on the internet to connect to a Tailscale domain and they will be connected to your server at home through a secure tunnel.
Tailscale subnets allow a device using Tailscale to expose devices that are not using Tailscale in their LAN to other nodes in the tailnet. So if for example you use Tailscale on your phone when you're on vacation and you have a subnet on a PC at home also using Tailscale, you can reach a network printer on your LAN at home even if that printer is not running Tailscale.
There's one more interesting thing you can do with Tailscale and that's an exit node. When you make a Tailscale device an exit node it will let other Tailscale devices connect to the internet as if they were the first device. It's useful when you're away from home at a hotel or airport wifi and want a secure connection, because the connection will be encrypted due to Tailscale. Can also be used to appear at home when you're traveling for whatever reason (trick Netflix in showing you the catalog from your home country, pretend to be at home when working remotely etc.) It acts like a VPN service in a way.