Perhaps, but I see a hidden bias in there that piercings and tattoos are inherently bad, lumped in the same category as slobbishness.
There are virtually no circumstances in which slobbishness is a neutral or positive sign of a person. That is not true of tattoos or piercings. They are only bad if the job calls for an appearance that is on the side of conservative.
And the requirements on appearance are always changing. I look at twenty-somethings these days and see maybe 50% have tattoos and/or piercings. That means in ten years, there's a good chance the interviewer will have tattoos and/or piercings. In that case, an interviewee's ink and/or posts might help to make a good impression.