Cool travel tool but is it worth using it to book?

I just found about a cool travel tool - farecast.com/hotels

How It Works:
You type in a location and it tells you how much hotels in that area cost. I checked against a recent deal I got on a trip to Miami SoBe (yes, going back again!) and found at least one hotel that was cheaper for the same dates than a rate I recently booked.
Farecast.com Sample Search Results - Miami

I do like how this tool gives you a sense of the greater picture. Once you select a hotel you can also compare hotel rates by season by hovering your mouse over a nifty bar graph. I stayed at the Wave Hotel last month and checked it out here. The description here is consistent with what I know about the Wave.

Making the Purchase:
To purchase, I was taken to a third party website, Reservetravel.com. I actually had the option choose a lower rate than what had shown on Farecast.
Reservetravel.com Purchase Page

Taxes and Fees:
Here's what the purchase page said about taxes and fees.
Hotel Tax is included in this amount. Additionally, in order to guarantee your room and guarantee your room for late arrival, a non-refundable deposit of $25.00 is included in this amount and is charged at time of purchase. This deposit amount will appear on your credit card statement as Alliance Reservations Network, Phoenix, AZ ... This fee will be subtracted from the total amount shown [above] and you will pay the balance of $508.50 to the hotel directly.

Not sure how I feel about the $25 non-refundable deposit.

1. The Sales and Occupancy tax is 13% in Miami Beach so it looks like you're paying $25 just for using this booking service.

2. The $25 "deposit" doesn't appear to be credited towards your hotel bill either. The hotel deposit policy is "1 NIGHT ROOM AND TAX WILL BE CHARGED AT THE TIME OF RESERVATION".

I don't know if you will always have to pay this fee when using Farecast as the third party reservation sites vary by the hotel that you choose. It may be worth it if you get a really cheap hotel. Otherwise, it seems a little misleading to call the $25 a "deposit." Also, last time I checked, hotels don't give away your room just because you check in late. I'm pretty sure you get charged a no-show fee or the cost of one night's stay. What is more, I believe if you are delayed and notify the hotel you are still coming that they will hold your reservation!!

Conclusion:
Neat tool but not impressed by the $25 fee or the explanation for it.