GST on Stamp Duty - Goods and Services Tax - GST

Hello, From my limited research I understand that GST is not applicable on Stamp Duty and the prominent arguments taken are - 1. It is a tax not a service. 2. It is exempt under SI. No 47 of NN 12/2017 For better understanding whether GST is applicable on stamp duty or not, I would like to invite views on following points - 1. Stamp duty is essentially paid to State to validate certain documents to hold them good in law. Definition of services under GST is so vast, can it not cover activity for which stamp duty is collected? 2. Section 15(2)(b) includes duties also for valuation, so can we say here that Govt s intention was to cover stamp duty also? 3. SI. No 47 of NN 12/ 2017 covers only service of registration under any law which is essentially collected under The Registration Act . But stamp duty is collected by states under states stamp act, e.g., Maharashtra Stamp Act . How can it be said that stamp duty is covered by the exemption? 4. Any other arguments for and against applying GST on stamp duty? Thank you in advance!