Digipeaters, like most other HAM stations, depend on operators that choose to deploy equipment for that purpose.

I used a 5W handheld today on my bike. You will see some long straight lines that are not following roads. Those represent gaps in the beacon system. My radio was probably beaconing on the order of every 5 minutes or less. On a bicycle, that is a lot of beacons and if there was 100% coverage, you would see them all and much more detailed view of my path.

I operate a digipeater and the beacons reporting from near my house are from my station.  We have two types of stations. Some stations just receive the beacon and retransmit it. Hopefully that will get to a gateway and go to the internet. Then we have gateways. Those stations send the beacons they receive to the internet.

Many stations, like mine, are both. They repeat the beacon and report it to the internet. The reason we still want to repeat is so that mobile to mobile beacon information is relayed. So if I send you a text via APRS and you are out of range of my radio, I may have my beacon picked up and repeated on a digipeater and you could receive the message.

I hope that helps.