Is it necessary to use Hangup in dialplan asterisk and what happens if it is not specified?

Question

Asterisk

Recently started learning asterisk and all my tests with dialplan were without Hangup, for example:
exten => _1XX,1,Dial(PJSIP/${EXTEN})
Calls between 101 and 102 go and when someone hangs up, on the other end short beeps are heard. A little later I saw that you can write it like this:
exten => _1XX,1,Dial(PJSIP/${EXTEN})
exten => _1XX,n,Hangup
At the same time, the behavior of asterisk has not changed in any way. Or am I missing something?

Answer 1

Optional, not strictly necessary due to auto-fallthrough, but highly recommended.
auto-fallthrough - if asterisk cannot find the next priority in the dialplan, it will abort the call.
Hangup() is an unconditional disconnect on the current channel. The asterisk documentation recommends adding Hangup as the last priority in any extension.
In general, everything is painted in the office.
Specifically, here about Hangup
And here about auto-fallthrough