In my opinion, the weakness of the bluewallet wallet is that it is not a wallet for storing large amounts of assets in the long term.
There is nothing inherently wrong with BlueWallet per se. It is in fact one of the most reputable and reviewed pieces of Bitcoin software in the space. It's the rationale; smartphones are the worst devices to trust with your bitcoin. There are too many things to account for when it comes to security implications; the integrity of the OS, the apps running in the background etc.
@hollowdoor, if you're going to buy a decent amount of bitcoin, please take care of your security seriously. There are numerous instances where individuals have lost their coins due to software exploits.