You can tell me all day long that passwords are not saved, you host 700 some odd sites, and that the files are clean and not comprimised.
What do you have to support your claim. Your word on an internet message board?
I've already pointed out the primary concern. Daily we receive pleas for help from WP users who've been hacked. Their host yells "we don't support 3rd party scripts", so we, as a community of volunteers, rally and try to get their site back up, no matter what the root cause is.
Add to that then they tell us they installed using your service. Now what does their host say? How do we then not know that your service didn't create a back door, even inadvertently. It then becomes one more hurdle in getting the site back up.
So despite your attempts at sounding sincere, I don't think you are going to convince anyone here who volunteers their time in putting out fires on other people's web sites, that your service is a good choice in installing WP.
Personally, I discourage using any automated installation, because invariably, at somepoint along the way,the user is going to want to install a theme, a plugin, make alterations, and if they aren't familiar with FTP, or editing files, then that's one more thing they have to learn before getting what they want.
If they take the little bit of time at set up to learn those skills, then they are that much closer to being independent in modifying their site.