You will rank better! Presell pages are placed on old, established authority sites that are note filtered by a search engine like newer site are – and having a page of content there linking to you will help you own site's ranking.

Pre-Sell pages are natural contributions to a web-site, writing about you - and of course giving your site a quality vote! Can you think of any way or reason to detect or devalue that ?

You will get more natural human click-thru traffic ! Your pre-sell page will rank for itself – giving you a second entry point in the SERPs! 

Again - this second entry point is the Presell Page unique advantage ! You will get a new source of traffic!

Presell pages are often called "the perfect link" – much more powerful than normal text links as they give the links to your site more topical context ("theming") and multiple key phrases are usualy linked - important for Search Engines latent semantic indexing and offering a good chance to optimize for multiple terms at once.

Presell pages have been used by professional SEOs for years - e.g. Dan Thies wrote about that 3 years ago already!