An annoying thing is that if you press e.g. a letter key in a
read-only buffer, you just get a message like
Buffer is read-only: #<buffer whatever-buffer>
If there is no use for most self-inserting keys anyway, why not
use them for scrolling etc.?
(setq view-read-only t)
changes that. Now all read-only buffers are automatically put inview-mode, irrespective of whether you don’t have permissions to
edit them or if you just press C-x C-q. How handy.