Yes, I confirm, the list images result is not so good.

Is it a good idea also add the ALT tag with the field Label text ?

Selecting the same image twice is probably hard to do given how a HTML select works. The output however could be adjusted. Each field type can use an own layout, eg the imagelist uses this one: https://github.com/joomla/joomla-cms/blob/staging/plugins/fields/imagelist/tmpl/imagelist.php
This is fully overrideable.

Of course it can be changed to a list as well in core if someone wants to do a PR. However without the needed CSS you will get the bullet points before each image which probably isn't what most users want :)

I would say that the ability to add alt and title params for each image is essential

For a temporary solution, use the image filename, replace hyphens and dashes with a space, and omit extension.

Minimally, add alt="". I vaguely recall that without alt attribute that the screenreader will read the filename.

Minimally, add alt="". I vaguely recall that without alt attribute that the screenreader will read the filename.

That is correct but it is also incorrect to add a blank alt param unless the image is only used for decoration