It's important to scan the references to check oneself if one agrees with the selection of references, or if the author(s) omitted important work that one knows and the authors did not know or did not want to cite due to a hidden agenda (selection bias), in which case one may email them to share additional references so that they cannot say "we never knew".
I could accept numeric citekeys if and only if the HTML rendering shows me the full entry when hovering over it with the mouse cursor (as a "tool tip"); there is absolutely no need in the 21st century to manually scroll/jump to the end without coming back when you can shop the reference inline. Hypertext is there for you to make use of it (Berners-Lee [1], 2000)!
References
[1] https://search.library.wisc.edu/catalog/999902745302121/cite ;-)