Most ads that don't include a phone number, are just come-ons to a credit card scam.  If you respond by email, you will probably get a response with a link to her "security" web site, where she promises to give you her phone number and other contact information , after you sign in and pay a small "security fee".  

Of course, all that really happens is your CC gets dinged, and you are left holding the bag, and probably yourself as well.

I have seen at least 2 legit providers with nothing but a reply button

I have also had some very memorable engagements that started with no phone but just email.  But most did not even have a photo, let alone one as bold as this one with a face pic.  

There is no harm in responding but do it from an anonymous email.  If you use one that may be linked to your facebook or business, all hell can break loose.