The payments in Bitcoin really have to optional and not mandatory because if it becomes mandatory definitely there are going to be certain negative feedback and sentiment from people hence payments should be made optional as to many that have seen the true potentials bitcoin holds and interested in it through personal conviction because definitely some people might not be interested and of course they shouldn't be forced to do so, but however and undoubtedly Bitcoin has really gained more wider spread adoption which a lot of people might regret for not getting involved with Bitcoin when theybfirwt had the opportunity to do so.
I don't think any government will even make it mandatory, they will just make it an option for those who want to pay using Bitcoin it is going to be fun and less stressful because when it is time to pay using Bitcoin you can even scan then send that makes it very easy, because even the word is advancing, it is just as if bitcoin has been in the future for a very long time and their countries that they made bitcoin a means of payment and I don't see them with any complain and since Dubai is considering to make it as another method of payment makes it more fun because it going to affect the price of bitcoin for sure. Dubai people are business people so they definitely have a reason for doing this, and other countries will pick an interest and might even want to give Bitcoin a shot because a lot of countries have been having issues with legalizing bitcoin and just a single decision can change a lot things so every decision is an opportunity to open more doors and that is what we want positive news always.