Good question. I think if one were to aim at a 1:1 question-answer and the question used ある, it would be more natural to answer with an ある answer. What I meant earlier is that if you’re just making a statement about something being “located” somewhere, it’s a little unusual to use です.
In Japanese the main difference is that ある is a verb and です not really (insert long explanation about copulas, also I’m not a linguist 
). You can have a sentence without the です part, but ある is actually meaningful. So for instance:
私の家は、図書館と銀行の間
is kind of incomplete, because は just marks the topic of the sentence, but we don’t really know what happens to it other than that something happening to your house:
私の家は、図書館と銀行の間にあります。My house is located between the library and the bank.
私の家は、図書館と銀行の間に建てられました。 My house was built between the library and the bank.