As others have said the intent is not to document sobriety but to have a subjective reason for an arrest which looks good in the scorecard.
Look for “if cops say I smell Alcohol, say these words” on YouTube, gives you tips on how to respond if asked about alcohol use or doing a sobriety test.
I am curious about these 'smell' comments, or at least how you're supposed to react to it. The last time I got pulled over, the cop commented multiple times that something smelled like marijuana, and he asked if I had been smoking or had friends that smoked.
I said I hadn't and didn't know anybody who did. It's true that I don't and had not been around any and there's no way my car smelled like drugs. I think I was on the verge of heat stroke and basically didn't respond with any level of stress to anything he said. I was being pulled over for driving without a seatbelt, which I almost never do, but it was 95 degrees and my AC was broken and I couldn't bring myself to put my back against the chair (plus I was in the middle of nowhere).
Another cop also showed up reasonlessly to hang around behind the other one with his lights on after awhile (I'd pulled into a gas station), which I think was also supposed to freak me out. I ended up excusing myself to go stand in the gas station to cool down and when I came back they were gone
I rather use a lawyer for legal advice than YouTube. There is a lot of sovereign citizen "you don't need a license to drive" "legal advice" on YouTube too.