They are buying those bitcoins in order to be able to facilitate those transactions, remember they've bought those ATMs, they want to provide the population with an easy way of changing BTC<>$ so they need a liquidity fund, and to be honest, I'm actually surprised in a good way that this fund was created, to me it's way better news than just buying a few coins and sending them to a cold wallet, it's a sign they are actually thinking on the next moves, not rushing things as they've done before. Poeple not being able to instantly transact from BTC to USD or the other way despite the promises would have been a blow nobody would have wanted.