There are several other cases that I can think of as well (like embedded systems). However, the main point is whether or not software is delivered to customers

There are several other cases that I can think of as well (like embedded systems). However, the main point is whether or not software is delivered to customers or is served to customers. Webapps/SAAS applications are clearly different because customers don't install anything and therefore version numbering from a customer perspective does not have any meaning. Therefore, any meaning we attach, is for internal internal consumption only. In even in that case, I would argue that version numbering is important. E.g the point on easier communication is exactly where internal consumption requires version numbering.