Hackers can't have access to your funds unless it's your mistake. About uses of bitcoin, bad people will use anything secure and untraceable and they will exist if there is a bitcoin or not.
I agree , If you are using an online wallet I have a suggestion , Use a new email on your online wallet and dont let it spread on any registration forms. Just make an email thats the main purpose is to use on an online wallet. We know email is hackable and when It is hacked , hacker can bypass the security of your online wallet. I am using many emails for different wallets and I dont register my emails into different kinds of registration forms especially airdrops.