Its definetly positive for BTC but I worry about the Novogratz 2018 mistake. He said 'institutions are coming' and he was about 2.5 years too early. Countries/Central Banks might be coming but they are probably even slower moving than institutions, they have elections to worry about, laws to deal with etc. But this will be a great case study, they will be using lightning so if the underbanked really gets banked and the country makes a bunch off their BTC holdings, then in a few years lots will want to copy it. But it might be a few years instead of months
I don't live in El Salvador but if I were living there and I had a small shop selling ice cream, for instance, I would have 2 wallets, a non-government version and a regular wallet that supports bitcoin lightning
So, let's say I sell $2 worth of ice cream and that's going to be enough to feed my family, those I will use the government version that allows me to convert to US $
The rest of the sales for the day, I will use the regular bitcoin wallet and that will be my family's investment savings account
If a day is slow or if we have emergencies, I can use the bitcoin savings to cover the shortage in funds, since every business must accept it as legal tender
But now, everyone, even the person who sells ice cream or sells fruits can have an investment account and if bitcoin doubles or 10x, they have the ability to increase their wealth by the same amount [edit: of course like any investment, they can also lose value]