Hi, most of the problems in the past about stolen money was caused by some leak in the online servers.

What guaranties do you put in to avoid being hacked?
If an attacker hacks your server, it can do whatever they want, specially they could wait for some big accounts to log in, send fake JS to the client, send a hacked updated version of the app to chrome, etc.
I only see that it is probably harder to hack than blockchain.info, but still you are somewhat vulnerable.

I'm not saying they would be able to sustain that problem for a long time, but one day or even some hours doing so could be catastrophic for all users using the service at those hours.

Am I wrong?