Why the heck would you do MFCC on images? Mel filters try to replicate the perception of human ears on audio. This looks like buzzword soup to me (SACC_Pitch, Tonality? What the heck?!? These seem like audio features - where are the formulas!).
I also don't know about your other conclusion, there is no reason you couldn't download this dataset given enough time/bandwidth/storage to process locally. Most people who will work on this could reasonably store a large chunk locally, if not all (~10 TB). This also assumes that you can't reduce/compress the info any further than what flickr provides and that you require access to the entire dataset - if any of the images are 1024x1024 or larger most feature extractions do not need that kind of fidelity. Heck, you could probably make use of grayscale only to reduce the size by a factor of 3 - ~ 17 TB is feasible (though still pretyt insane) to store locally.
ImageNet (~1.2 TB) only took me 45 days on a residential (<20 MB connection), and I wold assume that this dataset would be downloaded by entities with much higher download b/w. I would also assume that many algorithms, like the type that attack CIFAR10 et. al., would also be willing to reduce the dimensionality and recompress, further reducing storage overhead. How big is each image?
Also, where are the hyperparameters they used to calculate all of these features? Extracted features aren't really that useful without context/reproducibility.
All that said, I think most of these features are decent and the dataset is amazing, but I would rather see them release the raw data set and its PCA/ZCA/other transform - maybe Gabor filtered etc. as well. Lower level preprocessing is more useful for doing representation learning IMO - these higher level features are not that useful for ML algorithm developers. SIFT is patented for heaven's sake! How are we supposed to build algorithms on top of things like that...
I am excited about the dataset but feel that there could be more done to truly enable researchers. This feels like a "look how much data we have/look how awesome and used flickr is" thing to me.