No, it's not an art style, it's a limitation.
Are you kidding me? Who makes arguments like that seriously? If limitations were not art styles, the only kind of art style we would have is as realistic as possible. Please tell me you were joking with that incredibly stupid comment. The only kind of art we would have would be photographs and photorealistic renderings.
Everything that can be done in palette mode, can be done in 24-bit colors (you just have to limit yourself to a certain pallette).
Here we go again... Yes, you
can eat soup with a fork but the spoon just does it better. You
can emulate palette mode with 24-bit graphics but
it's inefficient, you're forced to draw each sprite multiple times for each palette you intend to use on it.
Here, I'll give you an example. Suppose we have 100 sprites of 16x16 pixels in size, 4 bits per pixel. 16 palettes with 4 colors each, 32 bits per color.
With palette mode, all this takes only
13056 bytes or ~13 kilobytes to store in memory. And you can display any sprite with any palette.
With 24-bit graphics as you suggest, it would require a whopping
1638400 bytes or ~1.6
megabytes to store! That's a
12549% increase in memory consumption!
And here's a suggestion: Why not render in 8-bit grayscale and do a post-fx palette mapper
Because it's not the same. You can't draw any sprite with any palette with that.
Now thankfully, you probably won't need every sprite in every palette in practice, but my point stands. It's more efficient. And
easier.