It's really not that hard to comprehend. Webmeeting is basically an enhancement that is included with the maintenance that relies on infrastructure that is not yours. The maintenance covers the usage of that infrastructure. Should you decide not to renew the maintenance, you lose everything that relies on 3CX infrastracture. So that would be the 3CX supplied FQDN, the automatic firmware updates and webmeeting. Keep in mind that webmeeting used to be a separate product that is now bundled with the MAINTENANCE and not with the PBX per se. All that being said, 3CX maintenance is so cheap that if someone opts not to renew it, there are probably other issues I'd be more concerned with.