Sometimes the person that reaches out for a demo is not the decision maker. They may be a user of the product with a vested interest in solving the problem. They may be gathering information for others.
If your sales process typically involves multiple parties, some who you haven’t met yet, send a follow-up email that is easy to forward to the other people involved in the decision. This equips them with what they need to represent your product internally (at least initially) because you already wrote up what they need.
See also: