I don't know to what extent tax issues (if at all) will affect European masses in adopting Bitcoin. I lack domain knowledge of those jurisdictions.

Capital gains tax is a non-issue in the developing world (masses here don't files tax returns). Yet they also are not currently the target demographic of Bitcoin.

The other issues I enumerated (look 2 posts up) should prevent Bitcoin from adoption of the masses for use as a daily currency every where on earth. Whether those issues will be fixed and whether they will be fixed in Bitcoin, offchain services, and/or an altcoin, is something that remains to be seen.

Right now Bitcoin is mainly adopted as a self-reinforcing (i.e. those who invest are supporting the rise in price, i.e. a sort of pyramid scheme of sorts but not entirely) speculative investment and some genuine use as a means to transfer value over distance. Also there are cases where one needs to use Bitcoin, e.g. buying drugs over the internet, registering domains anonymously (if you are very careful), etc.. Mostly Bitcoin is used to speculate in Bitcoin and altcoins. It is an investment unit-of-exchange. But none of that is really widespread mainstream use. I am still searching for that compelling need for the broader population.

One of the big needs I expect is when the confiscations begin, there will be a rush into crypto-currencies. Yet I expect an anonymous coin will get most of that, if that anonymous coin is respected and well established and is competing very strongly with Bitcoin (i.e. perhaps 1/10 or more of Bitcoin's market cap). Otherwise Bitcoin will get most of it.