I like to see them as bringing together "like-minded" people, or those with a similar interest. That can further whittle down to only including people with "X" vehicle type/years, or be a more open-ended welcome.
Personally, I always used them to meet the local gear heads as I moved to different parts of the country. Initially, it was just 3800/GTP/etc. meets with local GP clubs in the early 2000's. As the market shifted away from our style of car (3800/W-body ending), modding got expensive/"all been done before"/limited manufacturers/etc... I was sure to expand to larger community shows as we all see them. Even when I was in an unknown area for 3mo (Cleveland, OH suburbs, spring 2003), I roamed the local cruises as a hobby, even though I got sick of seeing the same stuff.
TLDR: Gives people something to do alongside people with whom they have a common hobby/interest. Limitations may be placed on participant vehicles, but search for what goes down in your area, and find what you feel like checking out.
Example: Moved to Central VA for work, and knew zero people, initially. Obviously got to know neighbors, co-workers, and such as time went on, but didn't know the car scene for seeing what people had for classic/modern/custom/etc. vehicles I felt like seeing & hearing (will eventually do the same at local 1/4mi strips, too). After a quick search, I found the following and use it to fill a free afternoon when I'm thinking about going out for a windows-down cruise:
CAPITAL CRUISIN'-- Cruise Ins
CAPITAL CRUISIN'-- Events & Shows
Free Listing of Cruise-ins And Car Shows for Antiques, Classics & more - Shenvalleycruisein
(just Google to find your own listings)
- Dave