1. technical weakness: we know its a peer to peer transection system throgh confirmed way. within a few second a dishonest person can get more money by fast clicking when submit second payment of different recipient.
2. proper management: there is so many lack of proper management of human or account holders. so many hackers want to hack system for getting money because bitcoins holder don't have any insurance like bank account holders. even government don't follow rules and regulation for virtual currency holders.
So what you think about it ?
Their will always be two ways of use of any think same goes to bitcoin, good way is to do investment in Bitcoin and earn high returns in long term, Bitcoin be used for so many good ways and for jobless users it is a boon to earn income through online. bad ways (improper use) of bitcoin is using bitcoin for illegal activities, gambling, paying for medicine which are banned in usage through legal way. So their are equally proper and improper use of bitcoin it is upto the users way of using it.