One bill instead of three
Building a voice agent on ElevenLabs Agents means three separate bills: one for ElevenLabs by subscribed minutes, one for whichever LLM provider you wire in, and one for telephony. When a rate moves, working out which of the three vendors moved it is its own debugging task. SpeechifyAI is a a single all-in per-minute rate, quoted per contract that already covers the LLM, the voice, and the workflow runtime, so the bill is one line and the rate stays put when the platform improves.