More slow buildup play/possession style=more time for the opposition to shove 9-10 players into defense and crowd the middle
Brazilian style is similar in a counterattacking sense where they play quick one-two's in fast attacking situations with space to exploit and usually only up against 2-3 defenders at a time max. Barca style is against parked buses with 5-6 defenders blocking you from even finding an attacking space or being able to connect with your teammates well. Most scenario's where he tries to play a one-two he'll end up playing a pass to his teammate, then trying to run through a crowd of defenders, but end up being completely separated from his teammate to receive the second pass and getting outmarked.
Usually the only way one-touch moves work at Barca is through more complicated triangular methods to find attacking space. To do that, the player must be able to make diagonal, inward, circular, or sideways runs at the perfect times to fluidly develop the sequence or create space for teammates. Also, the player has to fit in well with his teammates and know their behaviors and usual reactions like the back of their hand. You have to be 3-4 steps ahead at all times and be playing the events out in your mind like a game of chess.
That's why Alexis and even Cesc have trouble fitting into our style of play. Their positive aspects are usually shown in situations that aren't completely tiki taka style. Cesc gets it more than Alexis does, but it's still difficult to fully understand. I figure Neymar will sometimes be able to make it work, but mainly he'll only be good by exploiting space left by defensive errors or beating stupid defenders in 1v1's. That's why I think he won't be a total success in Europe. He'll score a decent amount of goals against weaker teams who make those errors, but will have a hard time exploiting those errors from teams as airtight as Bayern, Juve, Madrid, etc.
He obviously won't be a total failure with 2-3 goals a season or some ridiculously low number like that. However I doubt he will ever warrant a 45 million euro price tag and he won't become as good as he is hyped up to be. Better to spread that money around the entire club for squad/depth improvements in attack, defense, etc. and focus on internal tactical problems and raising youth rather than spending all their time and money to bring a star name to the club with the false expectation that he will automatically improve the team. It's idolizing him to be the savior in a superstitious way while ignoring the obvious practical problems that can and should be fixed to keep the club at an elite level challenging for major trophies on a yearly basis.