There are few users, who mentioned that they do not use Dalvik. And their voice is loud.
But there are a lot of topics and questions on both maemo and TJC about android apps.
Whatsapp and AFAIK facebook are available only as android app.
And as i have no Jolla on me and web page of harbour does not have feature to show apps - I can't tell you how many downloads android apps and dalvik itself have, but as I went to aptoide - the Jolla one (and it's not only the place android apps are downloaded) and there are 900k downloads. I think this number will tell by itself, or you think 10 people just redownloaded the same app?
Do not forget that there are more than dozen phones out there
In most reviews and post people describe how to use android apps.
Jolla itself promote android apps.
Basically we both do not know the answer - but common sense would tell that while dozen people can use Jolla phone as ssh terminal and compile things, majority - doesn't do it. Majority uses end-user apps.