If you want to connect a "regular PC" to the real world, you can get a USB DAQ but even the cheapo LabJack, NI or MCC models are at least a hundred bucks.
The GPIO on the PI is compromised for any hard realtime usage by the fact its running linux (ignoring what can be done with a lot of extra work with a RT kernel and pinning cores).
For non realtime use, the $10 USB->GPIO ones work fine on any computer with USB.
In fact many of them are just ESP's, and work even better than the pi for hard real-time because you write custom bitbanging ardunio code and send the results/control signal over the USB. They become custom peripherals with a /dev/ttyUSB endpoint.
with circuit python (basically Micropython) from adafruit you can open a screen session to the USB port and get a REPL interface. I wonder if you could set something up to script input and output from REPL (i'm not a python expert). If you could then you'd have a little pipe to the micro-controller where you could enter python and have it execute and return a value. From there you have all the GPIO and other features available on the microcontroller available to you on your computer.
I have one of adadruit's RP2040 boards and use the REPL a lot to talk to other things connected to the i2c bus. For example, controlling servos from a servo board, or getting orientation data from an IMU. Basically, i treat the circuit python REPL like a command line
Sure, in many cases. Depending on the situation, though, it may be no more hassle than any other USB GPIO device, so it's a decent enough cheap solution if you can't or don't want to use a Pi or a similar SBC.
If you want to connect a "regular PC" to the real world, you can get a USB DAQ but even the cheapo LabJack, NI or MCC models are at least a hundred bucks.