SaaS vs. Free Ads: Why is everything locked behind a subscription paywall?

Hey makers,

It seems like every micro-utility today is forcing users into a $9/month SaaS subscription model. Even simple invoice makers lock your client lists or history logs after 3 invoices.

For OnlyBills (https://onlybills.netlify.app/), I decided to keep 100% of the features free, including unlimited history, backups, and client records. To support the hosting and development, I'm displaying clean, non-intrusive ad banners.

My question to the community:

• Do you prefer free tools with banner ads, or would you rather pay a monthly fee to avoid ads entirely?

• As a builder, have you had better success with ad-supported utilities or freemium subscription paywalls?