Having a cocktail only event does allow a host/hostess to offer more variety while forgoing conventional catering's format which requires lots of dishes which can add considerable expense to your event.
Finger Foods - those delicious morsels that one can finish off with one or two bites are a great alternative to convential formal catering.
An event catered exclusively with finger foods allows the expense that would've been spent on dishes to go towards more food choices to be offered to your guests. Of primary concern to a host is that their guests are fed well and do not leave their event hungry. With a well thought out custom menu of hors d'oeuvres, one can have more than enough variety to replace a meal and have well fed satisfied guests.
For your next event consider having a full menu of small bites. They won't necessarily translate into a smaller price but will offer you the flexibility to have more choices.