To expand on
@etimal 's take.
What makes a CD Player is not that it is playing CDs. A lot of devices do.
Portable players do it very poorly.
What makes a CD Player is its use of the features allowed by the medium.
Which is exactly what most disc players on the market right now do not offer since
it starts with a full informative display.
The japanese brands dropped the ball years ago. Every single recent asian effort missed the point or showed a clear misunderstanding of record playing as an activity.
CD did not invent playing music, but it brought a way to do it better.
A real CD player is not living in the same dimension than a DVD player.
Maybe one has to experience it to understand the extend of this laconic remark.
The most defining features for a real CD player are:
- Direct Access to each track (meaning a dial pad!).
- Visualisation of the totality of the tracks available on the disc with an icon/number for each, on a indented line or a grid (meaning an info screen).
- Time and timing information in every possible situation : track, disc, sequence currently playing, elapsed/remaining.
- Custom sequencing of the tracks (meaning a program mode).
- Random Playing (meaning a random mode).
- Extract playing (meaning a scan mode).
- Repeat of selection, even within the random play mode that should support repeat too.
- A-B repeat of a section within any portion of the record.
It includes the legacy features :
- Quiet operation.
- Direct play from closing of the lid/tray/etc.
- That funny eject button (well ... it was fun in 1982-1984 ! Just search : Hitachi DA-1000)
- GAPLESS AUDIO PLAYING ... since it's not even a given anymore!
The only "modern" features truly needed :
- A great internal DAC/Headphone amp combo.
- Dual physical digital out (Optical and coaxial).
- Bit perfect digital Out (not just the internally produced upsampled then downsampled stream).
- CDR/CDRW and FLAC play
- 12v trigger since it's becoming a standard.
Having a CD Player doing DAC duties is neat but to add peripherical complexity and cost does not make it a better player; that's an orthogonal feature.
Today's Denon/Yamaha/Pioneer/Marantz/Tascam models do not bring even half of this feature set list that was a given on most of their own mid level players 30 years ago, and there were more to be had : digital volume, pitch control, fader, peek volume locator, etc.
Nowadays the portable gadgets we see online do not bring much more fonctionality than a $80 blue-ray player with an optical digital out. A point which does not erase the fetishist lust a MoonDrop DreamDisc can induce...