It's not wrong in a moral sense.

The "wrongness" is in it being a significant conflict of form and function both because mice and keyboards are heavilly used and the changes for form make them less robust and because the standards of communications for those devices were made to support the function not the form hence special software is needed to support the non-standards stuff that's only there for form.

Beautification of heavilly used manual tools is highly constrained by robustness needs and ergonomy considerations and in this specific case, by the standards themselves that support those tools (i.e. USB-HID).

Also at a personal level I find blinking lights to be a cheap form of design because it's so simple and cheap to implement (I can make a device with configurable multi-colored light cycles with all of a 1x RGB LED, 1x $.05 microcontroller and 1x push button - it's pretty much an Arduino entry level project) and requires very little artistry.

There are some trully beautiful ways of using light and then there's the typical kind of use of light in "game" mice and keyboards which is visually very basic, probably both because the people designing mice are not that great designers in the artistic sense and the "work of art"-level design wouldn't work within the ergonomic and price constraints for mass produced mice. (I suspect trully beautiful mice can be made, possibly including striking artistic lighting, but that probably requires much more expensive base materials than plastic - things like titanium or fine woods - combined and shaped in complex ways thus with much more expensive processes for manufacturing the housing)