Processing many transactions per second which today looks like an issue will be solved in future, the development will go on and I am pretty sure that Crypto will beat Visa also in this aspect. The first steps in this direction are coming with lightening, yes will probably need years but will be solved.

My concerns go to governments, national banks and the today's power holders. They will not let you get rich, they will fight with all they have IE the mass media, influence. They will and already are trying to convince people that BTC equals criminal, drugs and terrorist financing. Then there are individuals who can manipulate Stock markets, manipulating crypot market for them will be like a kids game. The weaknesses and vulnerabilities of actual decentralisation, this are the real issues.