I get what you're saying, but here's some benefits of using CF:
1. Been using it for 3+ years. Whenever I'm making a site, there's nothing better than easily making some DNS records and making sure they're all always-on HTTPS.
2. A little bit of the first part: It's a hassle to setup my own certs, etc.. I feel that Cloudflare "protecting" my IP from DDOS and other attacks is far better than anything that I can setup easily (at least from my experience, I think they know what they're doing)
3. Maybe in the future when I have some time and money I'll do everything on my own and ensure I have E2E encryption. At the moment, anything I'm running isn't mission-critical and isn't used by hundreds of people; I'm not making a SaaS startup. I understand your concern, but the ease of use of Cloudflare is something I value.
4. Analytics. I've come not to trust Google Analytics at all. I'm not sure what they're doing, but most if not 100% of tech-savy people have adblock, which blocks GA. My VPN from AlgoVPN blocks GA and anything related to GA, FB, Twitter, etc. So I'm not really sure how much I can trust GA's analytics opposed to Cloudflare giving me the exact numbers on how many people requested or visited my site. (I'm going to make my own analytics soon since Fathom has turned to profit only and not open source).