The word 'junk' on Buyee/Japan's online marketplaces doesn't mean what it does elsewhere. It can mean anything:

• Not having a charger on hand, so it can't be tested
• Literally just dusty
• They don't know how it works
• ...all the way to actual issues (which typically I've found are things like muck in the power switches which isopropyl alcohol fixes right up!)

Junk absolutely doesn't mean they're broken! Listings tend to go into a little detail on what is wrong with the consoles :)

I've bought a TON of handheld consoles through Buyee. DSi's (I got a great DSi LL in box with all the bits, barely used for $52 AUD), GBA SPs, I even got a launch Switch to jailbreak from Japan!

I actually wrote a article on a 'junk' PSP from Japan, you can read more on it here:

https://gardinerbryant.com/i-bought-a-junk-psp-from-japan-heres-how-it-went/