It's important to understand that a) NO ONE knows exactly what programs are going to do and b) programs get very different amounts of signals.
The data shows that competitive programs got a disproportionate amount of signals last year (some, more than they had interview spots) and other programs barely got any. This means a LOT of applicants wastes their signals on programs they had no chance of interviewing at.
Programs that recieve more signals than interview spots MAY choose to interview only people who signal (I need to emphasize again: no one knows exactly what will happen because this exact iteration of match variables has never happened before). Other programs are likely to recieve fewer signals than interview slots and therefore will inevitably also interview people who did not signal.
Overestimating your own competitiveness and signaling programs you aren't competitive for is, imo, a preventable way to set yourself up for failure to match along the lines of submitting ERAS late or submitting a personal statement talking about how much you want to be a dermatologist.