Bitcoin=Gold Ethereum= ICO FTSE but future everyday spendable digital coin = ?

So ive been thinking about digital currencies and here are some of my thoughts -

1) Will Bitcoin ever be used as a currency or is it in fact being the first crypto with small total limit instead just an investment hold asset like gold?
I dont know how i'd feel about spending Bitcoin casually and at such a high value with currently 16.7million in circulation its increasingly difficult to mine and going into such small decimals for transactions. Bitcoin = Gold?

2) Looking at ICOs and the majority building off Ethereum Blockchain (387 and growing), it seems to me that a lot of these great companies are yet to come to being market ready until 2018 (also alot to still crash by beaten by competition or finding out centralised systems work better in certain domains).

All the attention is on BTC at the moment but i believe Ethereum perhaps next year if not within the next 5 years is going to see a massive surge. Could we view Ethereum like the FTSE equivalent for decentralised companies? What are peoples thoughts with Ethereum and long term growth?

3) Finally BTC - 16.7 mill and Ethereum 95 mill coins in circulation is that truley enough for a one globally reckoned and spendable coin? Something you could spend your taxes on and buy a car with for instance? Ripple? Dash? Monero? Ripple has 38.6 billion coins which for long term world wide scalability seems good?

I would love to hear your thoughts!