The web killed software versioning. Do we really care what version of HN are we reading? Or what version of Github are we using? Not at all, we just use it. Browsers are moving in that direction as well, same as OSes like Android and iOS.
Update the parts whenever needed without the user even noticing.
Not all software are webapps (though I agree versioning is much less important, particularly for the end user, in those cases).
For those of us writing enterprise software that gets installed/ran by customers versioning is pretty important:
* Unlike a website not all our customers are using the same version, so when a bug is reported we need to know what version it was encountered.
* Customers need to know if version X of product A is compatible with version Y of product B.
* Gives customers an idea of the magnitude of changes, e.g. bumping the minor version will usually indicate mostly bug fixes, security updates, and small/non-API-breaking features.
* Facilitates easier communication with QA, beta testers, etc than referring (only) to a build.
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.
In my world versions are absolutely necessary. People need to be able to exactly reproduce what they previously did which means they record the version of everything they've used in the process, often to the point of md5 hashes or gut hashes or what have you. This also includes particular docker images for the OS.
Oh yeah? And how do you tell customer support on which version you've experienced bug?
As a user, I especially want software versions to know what I'm using.
I hate it how Facebook pretends that some features are bugs (for example - switching from most recent to top stories in my news feed) and I want to be able to report this, but I'm kept in the dark in regards to versions, changelog, basically everything except the UI.
...except when $somewebsite goes from 1.x to 2.0, and you hate the interface. This recently happened to Last.fm — i would give my first-born for the legacy interface.
Update the parts whenever needed without the user even noticing.