[natvod]

Writing effective one sentence product descriptions can be boiled down to:

Describe in simple terms a major product feature that either or both:

a) solves the biggest pain point for your customer

b) makes you the most different from your closest competitor

Examples:

https://heapanalytics.com: Automatically track all website and app user actions - no coding required

https://mailchimp.com/: Easiest to use email marketing platform

https://www.pipedrive.com/: Drag and drop interface CRM - view all deals by type at a glance

https://www.getrevue.co - Effortlessly send a weekly newsletter to engage your audience

http://www.artofemails.com/ - Proven prewritten sales email templates

[hammock]

You took one point from OP ("lead features") and missed the others.

For example, the "input output" part. Without that you are probably missing some representation of the user/customer in your description.

Ab rollers would never sell if they said "gives you rock hard abs" without the "just 20 minutes a week!" part.