My understanding is you make fewer but more replicable mistakes. If you use a wire you have to trace it, keep the length consistent for timing reasons, use very consistent soldering technique, and ultimately you have a hard time tracing issues. With a homemade PCB you generally do get what you ask for in terms of circuitry. Traces are the right length, right thickness, right spacing, and if not then the whole board is similarly impacted, so it is obviously broken or not broken. If you mess up your design then you have a problem, but if you did the process right and you have a valid design then it works.

That all said, homemade PCB is a large time sink and modern PCB manufacture is so cheap and fast it doesn't make sense to do at home for the most part. You can literally get a complex board faster by ordering it from halfway around the world and having it posted than making it yourself. I would say it is a good learning exercise, not a good manufacturing or prototyping practice.

I mean, if you put in the work to figure all the stuff out when the alternative is to pay $400 for 5 pcbs that take 2 month to get delivered, then yes it is a more viable option. Luckily that's not the case anymore, but if things so south in China I imagine the only hobbyiest pcbs you can get will be via this method again.

You'll have to modify or build a heated laminator until it can apply photoresist film perfectly to a sheet of copper clad fr4. The you'll have to build a uv exposure chamber and a light diffuser (I used a picture frame and a shower curtain). Then put that on a turntable for even light distribution like in a microwave and figure out some way of pressing all the layers together tightly enough so it turns out right and light doesn't get under the clear stencil you printed the pcb layout to. This will take a lot of trial and error to get right. Then you have to figure all the variables to get it to etch properly through even more trial and error.

Once you have all this stuff figured out, you have to figure out a way to deal with vias. The best way I found was to manually solder a wire or pin for each one and make sure to make them big enough that this can be done by hand. Keep in mind that regular through hole pads won't be connected on both sides so you need to solder the unused ones for your design to work out.

I wouldn't go as far as to call this "worth attempting", especially if you're trying to make stuff more complicated than an 8 bit computer but for really simple stuff that doesn't require high precision, super thin traces and lots of vias, it's not too bad. Simple designs won't require the same levels of process perfection as trying to make something like an atx motherboard.

Only as effective as your layout skills :)

Check out jlcpcb. Honestly insane what is available to the hobbyist of today