Am I nuts?

Never anything to lose if the price is right. But when it comes to digital, the happy path to best sound is go latest and greatest that checks your boxes. Need not cost much these days but many options to choose from. Going old school may be easier in that sense. Digital these days can be pretty confusing. But the good news is there are many options and most of them are good, much better than years ago.

For example you could play your CDs on a computer and go digital out via USB to a nice modern good sounding DAC. Or be brave and explore ripping CDs to a library and streaming from there. That’s what I do. I buy CDs still but never play them....I rip to library and stream from there. Free version of Plex can be used for that to start.  I would recommend exploring that option at least if you are at least moderately computer savvy. Still maybe not for those who are not.

How stupid is that?  I think you answered your question already.  Why would they sell a 15 year old CD player?  Maybe they are streaming hi-res music instead and they are joining the new century.

It's just a disposable product like a phone that you can't change the battery.  If you are willing to replace it when it dies and the calculated cost per hour used is acceptable, go for it.  

If you really like that model more than something new just find a backup model and figure that it really costs more to get you what you really want.

I like to use a CD changer. I saw and old Onkyo at goodwill for $39. I bought but it was skipping a little. I used the CD lens cleaning disc. It really sounds good now. I have it in my second system so if it fails I will probably get another used one. Ebay has a lot of them available too .

Like in gambling (as this is I guess), if you can't afford to loose the amount of money in question, it you shouldn't play with it.