Tried YouTube promotion beta, sus outcome

I used this beta in the YouTube studio to promote a meme short I made for valorant. Thought it was funny enough up pay for a promotion. I ended up using 50$ and got 1k views and 150 subs. Doesn’t seem to add up in my mind that 15% if these 1k viewers decided I’ll sub. When 8k before viewed and only 10 subbed. Anyone else seeing some sus outcome of this?