You can justify projects in a number of ways. One of the simplest to think about could be FTE save. Does it save you 10 minutes a day, 5 days a week? Does it save 3 people 6 hours a day once a week? You can convert any expected time saving to an approximate dollar value by assuming a ~2000-hour work year and pinning an average worker's salary to that. If an average salary is $100,000 a year to make my math simple, then you only need to save maybe 5% of an FTE's time to justify the license.
Moreover, you can think about risk reduction as well. If your AR processes are being run manually, by a team typing things into spreadsheets, then there's a lot of room for manual input error, and in systems that touch cash, that's expensive! Those teams will probably have some stats or some horror stories about financial losses caused by human error, and the great thing about using Alteryx is that it can easily eliminate many of those types of problems.
If you're looking for testimonials, maybe look for general use cases along the above lines rather than use cases specific to your industry niche. All industries share common problems that automation can solve, and since Alteryx works with so many types of data, the success stories from one industry will be very applicable to others.
