It had also removed higher value bak notes two years prior: https://www.washingtonpost.com/world/2018/08/29/india-replac...
Both initiatives born out of curtailing criminal activities of various kinds at the time.
So the crypto ban happened during this period and may well of been born out of that initiative against crime more than anything else and now that things have settled down, the need for the ban became moot.
At least that is my thoughts upon this.