It's a really, really slow computer. The Pi 4 is something like 10x faster than the original Raspberry Pi, but that was also a really, really slow computer. I remember not wanting to set up a cross compiler once, and recompiled ntpd on one. It took more than 24 hours. The same build runs on my desktop in seconds.

It is good for things like reading a sensor and sending it to some server, but so are ESP32s which are cheaper. You are paying a heavy price to get video output and Linux compatibility. In the current era, it's a bad microcontroller (expensive!) and a bad desktop computer (slow!). When it came out, most people were using $25 MCU boards, so $10 extra to run Linux was a great deal. These days, a massively more capable MCU dev board can be had for $4 (if you want free 2 day shipping, less if you can wait).