Interesting, but my testing suggests that SplatHash is very weak at preserving global features, at least for synthetic images [1]. Both BlurHash and ThumbHash were able to preserve most of them, at the expense of worse (but still non-zero) local feature reproduction, but SplatHash simply discarded all global features! I guess you need to store both local features (Gaussian splats) and global features (cosine bases) for the best result. The currently unused padding bit might be useful for that...

[1] I used my own avatars and icons as a test set. For example, https://avatars.githubusercontent.com/u/323836?s=400&v=4