I see no evidence at all that this particular dataset is better than MNIST. None of the issues they themselves list with MNIST are discussed with relation to their proposed replacement.
The benchmarks they provide are entirely useless - sklearn does not claim to be a platform for computer vision models. A quick WRN model gets 96% of this dataset (h/t @ajmooch on Twitter), suggesting that it doesn't deal with the "too easy" issue.
The images clearly don't deal with the problem of lack of translation invariance.
On the downside, they don't have the same ease of understanding of hand-drawn digits, which is extremely helpful for teaching, debugging, and visualizing.