How does "pay for fresh" relate to SERPs

What are the benefits of "pay for fresh"?

[gmoney]

I can see the benefit of search engines offering pay for inclusion so that one can quickly get your site included in their index. However, I am trying to understand the “pay for fresh” aspect of their service that they all seem to boast about in one way or another:

alltheweb – “ongoing refresh of your content every 48 hours”
teoma – “Your Web Page will also be refreshed every 7 days”
altavista – “Keep your page content up to date with automatic daily refreshes of your pages”
inktomi – “frequently updated (every 48 hours) in the Inktomi search engine”

It seems to me that all that really matters is how often the search engines update their results pages. Sure they can spider your pages every few hours but if they only update their results pages every few months then frequent spidering seems like a silly thing to boast about. Do some of these search engines actually update their listings and RANKINGS continuously with "fresh" spiderings?

Basically, I am trying to understand how “pay for fresh” relates to the search engine results pages. I would be interested to hear how/if any of you have benefited from having your content "refreshed" frequently.

[heini]

It's great for sites with continually changing content, special offers for example. Also: if a page doesn't work with the users, just change it, and here you go.

Ranking: well, doing some finetuning and seeing results quickly is not a bad thing.

[gmoney]

Heini,

Am I correct in assuming that if you changed a page to a completely different title, description and body then your listings and rankings would be changed/updated within one “refresh” period.

Are alltheweb, teoma, altavista and inktomi all like this? If so then it would be great to experiment with their algorithms. Maybe this “pay for fresh” business is worthwhile afterall.