That is categorically not true. Showing why something does not work (or is not advantageous over other methods) demonstrates you know how to properly conduct research which is good for ones resume.
The paper is irrelevant and will never get cited. There is essentially zero benefit to your career as it is nothing more than a single bullet point on your resume.
Discovering something that works is significant, discovering something that does not work is irrelevant.
Can you name a single scientist, e.g. from your field, who is known for showing that something does not work?