The article does not use LSH as it is typically used. Typically, LSH is for low dimensions - you split the space to cells by the hash value, use the hash value

The article does not use LSH as it is typically used. Typically, LSH is for low dimensions - you split the space to cells by the hash value, use the hash value as an index, and look up one to a few values for every key (so you have some overlap). In contrast, in the article, we use the value not as a hash but to construct a metric, approximating the original metric space. Then, we do a full scan with filtering by the approximate distance. It speeds up the search because a low amount of data is scanned, but it is not like using the hash for direct lookups. You can name it differently, e.g., "quantization into bit-vectors".