That's by design. It's basically gambling.
In my experience, buying packs with FC points gives better rewards than those purchased with coins. Coincidence?
They also front-load the reward packs. That means that your first pack generally has the best rewards. You think to yourself "Wow! This pack was great. I should buy another one." So you do. The next pack is absolute garbage. But you are still happy over your first pack and think "My luck is 50/50. Those odds are still good. I'll buy a 3rd pack." Another bare-minimum pack. "Okay, I'm 1/3. Bad luck can't last forever. I have to pack something good... eventually." And you keep buying because you're invested, chasing that same dopamine hit from the first pack.
They also have their "payroll players" opening packs via social media to get you excited because FOMO.