One benefit is avoiding screen time. You can't get sucked into your phone/computer if you don't touch them. Looking up a piece of information using the smart speaker helps prevent distraction.
Another benefit is if your hands are full. For example if you're cooking or driving.
Another benefit can be speed. If you're doing something in your house near the smart speaker, it's probably faster to ask it a question than to pull your phone out of your pocket, unlock it (I only have a password, not fingerprint/face ID), and type in the query. For people who are slow at typing, this benefit is larger.
Another benefit is if your hands are full. For example if you're cooking or driving.
Another benefit can be speed. If you're doing something in your house near the smart speaker, it's probably faster to ask it a question than to pull your phone out of your pocket, unlock it (I only have a password, not fingerprint/face ID), and type in the query. For people who are slow at typing, this benefit is larger.