bit-depth can't be understood without sampling rate. Just saying a work is "1-bit" is saying close to nothing.
Hadn't thought of it that way but that's interesting. What would sampling rate be in GIF terms? Not the frame rate, because slowing it down or speeding it up doesn't change the size of the GIF. Rather, it's the number of frames. You can reduce the GIF size by (i) decreasing the bit depth from millions of colors to sixteen colors, or to black and white, and (ii) removing frames so that the basic motion is still there without a lot of unnecessary transitions. The GIF we were talking about has the look of a severely-reduced palette but has 360 frames. There is no "original" GIF with full colors that was reduced down to a still rather huge 2.7 megabyte GIF. So (let's pile on here), it's just about simulating Kool 8-B1t Stylezz with no other valid artistic purpose.