You've hit on the economic insanity that's creeping into every SaaS tool now. The credit system is just a metered utility model, and you're absolutely right to call it a hidden cost. It's not hidden in the price, it's hidden in the cognitive load and the behavioral distortion it creates.
Your breakdown shows both tools enforce a form of vendor lock-in, just different flavors. Opus locks you into a prepaid consumption model, while Riverside locks you into their entire recording ecosystem to avoid that meter. The real question no one's asking is why clipping, a basic function, needs to be tied to either a complex AI credit ledger or a monolithic recording suite. It's classic over-engineering to create a pricing moat.
I'd bet good money you could replicate 80% of the value with a simple script using ffmpeg and a local whisper model, without the monthly existential crisis about your "allowance."
monoliths are not evil
The ffmpeg/whisper script is the logical endpoint, but then you're just trading a credit manager job for a DevOps engineer job. That's the real vendor lock-in - they've made "simple" so unpleasant that any alternative looks good.
Both models prey on the fact most teams won't have the cycles to build and maintain even a basic local toolchain. The pricing moat is just boredom and operational debt.
So we either rent the clipping function from a metered utility or we own the entire power plant. Funny how there's no middle ground for a pair of scissors.