I have recently read "The Mom Test" book (my summary https://blog.kowalczyk.info/dailynotes/note/b4u674cvj43jdajdsukg-summary-of-) which was an eye opener for me when it comes to how to interview people to validate ideas.
I recommend everyone to read it (or watch the free videos as they cover the same material).
According to the book "a fair amount of interest", "enjoy the thought of" are the typical polite brush off answers that don't actually validate the commercial viability.
Now, maybe your actual questions were more pointed.
Per the book, the questions that you would ask in this situation are more like: are you currently using (and paying for) online forms?
If not, then they are not your potential customer.
If yes, then you wouldn't ask "does feature X seems useful?" (priming them and putting them in a yes/no box, which is also polite/jerk that crushes your dreams box).
You would ask "what are the difficult things about using this solution" and then you would dig deeper to figure out if what the difficulty is really a pain point or a minor thing they came up with just to say something.
As an aside, at first glance I don't see how your solution is any more "brandable" than wufoo or, I assume, any other mature form builder. Customizability seems like an obvious feature to have.