I am aware that XLM will be a great currency, I think, it will be much better than Bitcoin. However, to be a currency, XLM must be used for transactions.
There are some features that a digital currency needs to have:
1. Fast: XLM can proceed within 3-5 seconds. It is about the same level with XRP.
2. Efficient or cost effective: I think XLM is cheap for transaction. I believe it is cheaper that Bitcoin. If XLM can be a free of fee transaction, it will be better.
I think, XLM can be a currency for the world as it is has much of those features. XLM is also run by non profit organisation, unlike XRP that owned by Ripple. XLM that will be granted to communities will make it easily adopted.
However, I recommend to Stellar Core to make XLM more useful:
"Build a decentralised exchange for any assets with free of transaction cost". On this exchange, XLM will be a native currency. XLM can be exchanged to any currency and assets on the exchange. In this exchange, companies like GOOG, AAPL, IBM, MSFT are listed and also can be bought here. Any assets including gold, silver can be traded on the exchange. Oil and Gas also can be traded.
If it can be made, i believe XLM will be widely used in the world. I have a dream that this exchange will be built. Just I am not a programmer to make a coding to make the exchange run:-)