I don't understand what use case they've given for SVD. Are they suggesting using it for compressing an image? Because that's a terrible idea, with an algorithm

I don't understand what use case they've given for SVD. Are they suggesting using it for compressing an image? Because that's a terrible idea, with an algorithmic complexity of O(n^3) and a very bad compression ratio. [edit] Just to underscore the point that you should never use SVD for compression except as a teaching example consider a comment here: https://mathoverflow.net/questions/408504/listing-applications-of-the-svd https://mathoverflow.net/questions/408504/listing-applicatio... The comment says That's a very nice way of getting some intuition about the SVD. But this is by no means an application of the SVD. Compression [sic] images this way is terrible by any standard (you get very bad image for still quite large storage and computing the compression is very slow). This is by an expert.