For the most part i am agreeing with you. If you take the output of a CD and run it though the players line outs to the line ins of a PC built in sound card. It is digital signal processed thru a D/A convertor to a A/D convertor in the SC. Whatever comes out of the CD player is going to be the analog equivilent of the Cd itself, and that is 16 bit 44,100 sampled redbook sound. Whether you send that to a PC sound card, a $100 USB, or $500 it is still 16 bit 44,100 sampled sound, pretty standard, and you are right it would pretty much sound the same.

I still say, after doing this for a number of years, myself, and helping a few dozen others setup their systems, that does not negate the value of a proper interface for a good recording system. The quality of the line in specs maybe better today, but the drivers and abilities to handle all the process of a full on recording session is not what those PC cards were made for. I have watched literally hundreds of folks come through over at the Cakewalk MC, every one trying to get the program to work properly with just a PC sound card, and after a lot of hassle, every one that went out and purchased a decent interface found the same thing. Their problems stopped immediately.

If all you want to do is transfer audio from CDs and or other devices to the PC the built in is more than enough. You want to build a real powerful do all studio the interface is the heart of that process, at least to me it is, form my personal experience. Nice thing is, that they are not that expensive anymore from around $100 to $200 you can get a butt load of them.

HP Win 11 12 gig ram, Mac mini Sonoma with 16 gig of ram, BiaB 2025, Realband, Reaper 7, Harrison Mixbus 9 32c , Melodyne 5 editor, Presonus Audiobox 1818VSL, Presonus control app.