The big ways it benefits you is because affiliates can't see that it is a referral URL and more to the point, they can't just whip your ref ID out of the URL bar or replace it with theirs.  It makes it much harder for them to steal or cut you out of the commission you would normally earn.

Also, as it places a Viralbar at the top or bottom (your choice), you earn credits to show your own ads on other members Viralbar and the ViralURL logo and link when clicked take them to your ViralURL affiliate link. When members join from there, they go in your downline and you are able to mail them.

Also, once they then upgrade, you earn commissions.  So basically, whilst promoting your other products, you are promoting ViralURL too, building yourself a downline and an income potentially on auto pilot (you are leveraging your current promotions).