Perhaps partly, but the UI was also useful compared to WMP. WMP was slow, bulky, and took up lots of screen real estate. WinAmp, while it was themed, was slim, but also packed far more control into a tinier space than WMP.

(The blue/grey theme that came later was far less performant; I mean the original dark green/black theme.)

And WinAmp would open & play literally any format under the sun. WMP was limited to something like MP3 and WMA. (And maybe WAV.)

When Winamp first came out, everything was single core. Decoding mp3 took a significant bite out available CPU. Winamp was relatively efficient in CPU in RAM, especially compared to WMP.

WMP plays anything the system has a codec for.

Making users care what codecs are and which are available on their system (and with no UI to even answer that question) is just another example of how bad some organizations are at UX.

That's how VLC became so popular. They realized "sorry, you don't have that codec" is only a bureaucrat's idea of good UX so they shipped every codec in software.

Ah, codecs. The biggest PITA on Windows in the 1990s/2000s. I went through two or three different videoplayers for the sole reason they shipped with whatever was needed to open just about any format out there. Meanwhile, trying to coerce WMP to open popular video formats was an exercise in futility...

> I believe Winamp became so popular because it had such a unique UI

Well, yes and no. Remember, Windows Media player used to be this:

https://www.windows-media-player.com/wp-content/uploads/2019...

and without system-installed codecs, which were hard to come by for something like MP3 files, it was basically useless; you could play MIDI files through your shitty OPL-3 FM synth and that's about it.

Winamp came with a remarkable set of capabilities: - A bunch of useful codecs out of the box - An extensible plugin system, with input, output, general, and visualization plugins - Skinnable UI

The secret sauce was the extensibility, really. You could kill hours just tweaking your Winamp, installing crazy audio effect plugins, and so forth. It was really a new breed of application for most users who were used to really business-like apps.

To corroborate your point, I loved fiddling with the Enhancer plugin:

https://i.imgur.com/DuxpATX.gif

It's what started my desire for better sound quality, pursuing better equipment and assembling my own crazy dsp stacks in order to... well, enhance sound quality, which I do to this day!

Dealing with equalizers, dynamics processors, crossover, convolvers/IR, applying hrtf/hrir found on the net, using room eq wizard to try and improve speaker/room response, buying a damn binaural microphone so I could make my own ears impulse responses... I ended up learning a lot about the subject, form such a tiny "seed"

The Winamp (classic) skinning was so brutally effective, considering how simple they were. AFAIK the bulk of the skin consisted of two or three .bmp-files which were spritesheet for all controls and fonts. Literally anyone could make one with a tiny bit of effort.

Now that screen resolutions vary quite a bit I suppose it wouldn't work as well as when all monitors were mediocre 800x600 or glorious high res 1024x768. Ah, the nostalgia.