Bayern Munich is just trying to milk some money from Barcelona because they know Barcelona is very desperate for this player and this player is also going to be very important for the future success of Barcelona. but if Barcelona wants to get this player they will have to get him for a short period of time because he is not going to be able to give his service for a long time in any club right now. and there is no point giving 50 million away for a player like that in my opinion. there is no doubt that he can perform really well but if he does not Barcelona is going to be in really big trouble.
Yes, Barcelona want Lewandowski because they expect him to boost the team's game in their attack. If they manage to get Lewandowski but what they hope doesn't happen it will be a problem for them too. On the other hand, in my opinion, an experienced player like Lewandowski will slightly reduce the risk of him playing not as expected, rather than having to recruit young players.