Even at the time of writing the OP, I felt that saying "they did it for performance" was maybe too generous, but I wanted to lend some benefit of the doubt. It could've very well been the case at a time, as the article about cave culling on mobile leads me to think that perhaps the developer atmosphere was "do anything and everything to make this game run well on (what was) today's low/mid-range phones, no matter how small (comically so in this case, as alluded to in your post)," with the various tricks implemented having since been left intact for reasons that I'd guess amount to lack of priority.
Whatever the case may be, if the end result is this...
...to call it ugly wouldn't be too far off, IMO anyways. Since yesterday, I've also noticed that, on Bedrock, even tree leaves lose their transparency (think switching graphics from Fancy to Fast) at roughly the same point as the vine/grass cutoff. On 360, the mip-mapping is so aggressive that the leaves become almost unrecognizable, but they at least are still transparent.
God, the more I talk about this, the more ridiculous I feel. I need a nap.