People use it because it is not a phishing wallet!

It is unfortunate that malicious servers were able to display fake warnings and messages but in order for a person to lose his bitcoins he would have to do several things wrong.
- Click on unknown links leading to fake sites.
- Download and install fake software.
- Not verify the digital signatures of the software.

All these are mistakes made by the users, not Electrum. Electrum's mistake was allowing the messages to be displayed and that has now been rectified but people are still downloading and using fake Electrum wallets.