The honest answer: it depends on where your customers already are, not which technology sounds more impressive.
If most of your inbound questions come through your website, WhatsApp, or Slack, a chatbot meets people where they already are. It's also easier to review conversation history and iterate on responses over time.
If your business runs on phone calls — bookings, intake, support lines — a voice agent handles that channel directly instead of asking callers to switch to typing, which a lot of customers simply won't do.
Deployed to the channel each type of customer actually prefers, rather than picking one and hoping everyone adapts.