If I splash a position to 100 why do I have to win a game on that position to get into series?

So in the worst case scenario, you will get a position to 100. You then have to win a game on that position to start the series, then you have to win 2 more to actually win the series.

So if you go 3-0, you will gain 0 lp during that scenario, as opposed to just 2 wins with no lp gains. However, every loss will give you an lp loss. If you go 0-2 in series you lose 2 games worth of lp, or if you go 1-2 you lose 1 games worth of lp. The series system is unrewarding and is rigged against you winning, and the fact that you cannot splash into your promos only exacerbates the issue.

Edit: I just realized I'm on my smurf when posting this, avoid the "ur not even lvl 30" comments because they are unproductive