Daphne,
If you read all the posts, you may have noticed that another member stated that it took them to a sign up page. Just like FS, Ancestry has a "free account" and a "paid account". They also have library editions for MyHeritage and Ancestry in different localities.
I am not suggesting or promoting any membership ( I have no loyalty to pay services). If there is a source with a "fuzzy" image" and that's all I can get, I will take it. Example FS does not have a military record, whereas Ancestry does, but the dilemma is a clear image, being unavailable, so people don't want it. My opinion is that, at the very least, it still qualifies as a source. I think Ancestry membership would suffer if free members had the same access that paid members had.
There is no incentive on my part to promote any paid site (or unpaid for that matter). There is no difference between FS and Ancestry with regard to the free signup, as only an email and password is required.
Sometimes, on G2G,I have seen people ask for someone with an Ancestry (or other) membership to look something up, and maybe they validate the record by email, satisfying whether the source is valid. It fulfills a need/
I compared two profiles of my own and added two identical sources, one from FS and one from Ancestry. The information was the same except for the often "fuzzy" image. one had very little advantage over the other, except it did show a fuzzy image rather than 'no image available".
That being said...
I do use sources that are from free sites when I can (as not being subject to the whims of financial incentives, but sometimes a profile may go unsourced unless you can go elsewhere to get what is needed. Sometimes I need to do that.