Define “good” or “bad.”
Smartphones are useful if you use the technology built into them. Most you can talk to and they talk back.
If I say to my phone “What time is it?” it speaks the answer.
If ask my phone verbally if it’s going to rain today, it tells me.
They’re useful for navigation, they’re useful in telling you how many steps and/or miles you walked today, they do make and receive phone calls too, and they do a lot of other stuff.
However, like anything else, do it in moderation. Don’t give up human interaction.