I used to run software on an old phone that basically worked as a camera NVR.

At some point the battery swelled up and I'm glad my house didn't burn to the ground. I only noticed it because the glass screen protector on that phone had popped off from the screen flexing under pressure 😮

As long as you have a way of monitoring your phones, or at least physically isolating them from important things, then you could probably do it without many risks.