"It delivers a full feature list for an impossibly low price, with expected compromises."
The '30-Hour Battery' specification refers to audio-only monitoring with the screen off. Continuous video streaming will drain the battery in about 10 hours, necessitating a daily recharge.
This is for the buyer on an absolute minimum budget who prioritizes a private, non-WiFi connection and a long feature list. It provides basic visual and audio monitoring if you are willing to gamble on build quality and accept low-fidelity video.
Anyone requiring a truly clear image, long-term durability, or a signal that can reliably penetrate multiple floors should spend more. The extreme low cost practically guarantees compromises in the sensor, screen, and mechanical components.