Yes, Bettercap can show you all the wireless Access Points in range.
The reason why you didn't see all of them (or any) depends largely on your hardware and on your exact configuration.
What is Monitor Mode?
When you put your wireless card into monitor mode, you tell it to forward every packet that it receives to the operating system and to any application that wants to receive them. This includes packets of an access point that you did not associate with (aka. "logged in").
This allows you to see everything that is going on around you, on the frequency you listen to.
What is a Channel?
While Wi-Fi operates on radio frequencies, people often don't speak about exact frequencies. Instead, they speak about channels. These channels define a frequency band, which is used to transmit data.
If lots of Access Points are configured to communicate on the same channel, then a lot of noise is generated and the quality of the signal will be worse.
In order to see all the Access Points around you, you need to listen on every channel. Since this isn't possible, you need to "hop" from one channel to the next - just like a radio when looking for stations. This means first you set your card to listen on channel 1, then on channel 2, then on channel 3, etc.
If you want, you can also include the 5GHz channels, which would allow your card to listen to both 2.4GHz and 5GHz traffic.