The sending to yourself, and not opening it was just an evidential system to prove your version existed before somebody elses. Nowadays, with platforms like youtube spotting copyright problems in seconds, it's vital to do it properly, so your music is tagged in the international system. It works pretty well.
There are potential issues of course. Distrokid are I think the market leaders. They are also well known for being judge and jury. They are very hot on artificial plugging of your music. You can pay to have your music promoted - easy with computers, they just hit your track from all corners in the world. If you do this, you risk an entire takedown, and there is nothing you can do. Distrokid are well known for just doing it. My backstory is where one of my tracks, that had notched up a few thousand streams suddenly went crazy on Tik Tok - millions of streams via tik tok - and Distrokid whacked me hard - not only no payments, but they froze my account removed the money and banned me. No recourse at all. I was doing great with them until that point. Now songtradr is my preferred platform, but I spread a few with others just to be safe now I earn a bit. I doubt this would happen to you and is a rare thing, but don't ever attempt to inflate your figures. Now, they warn you every new release - they make you tick a box saying artificial inflation will result is bad things. Just be aware.