On a quick overview of the candle charts it looks like the overwhelming majority of alt coins serve no real tech purpose and is basically just pump & dump schemes.
There's a few kinds of projects that fall into the 'no utility' class...
1.)
The 'why the hell not' token: Anyone can create an ERC20 token (tokens on the Etthereum blockchain which is what the majority of these projects use) and a lot of people do. They serve no utility, the creator was just playing around experimenting with the technology. A lot of these creators attempt to push their creation forward...
2.)
Does nothing but we love it: Sometimes a community forms around these creations and they support the project even though it doesn't really do anything different to the neighboring ERC20 project.
3.)
Much hype over nothing: Fancy websites and mega-sized Telegram channels - the token does nothing special, but the sheer marketing and numbers carry it forward.
4.)
The scam: Token is created for the sole purpose of being dumped by the creator when the price is high enough.
Do yourself a favor and take a quick look at this link and see how many projects there are, even just on that first page:
https://bitcointalk.org/index.php?board=240.0
There's just so much nonsense out there.
And yet...I'm not always opposed to some of the categories above - there are some genuinely nice communities formed around those projects. My fondness for some of these projects stems not from a belief in their utility, but from the opportunity they provide to witness a global collaboration the likes of which I've never really seen before. People from around the world working together to build something and yes - I realize it's often a castle in the sky, but if the entire crypto space crumbles away tomorrow, I'd like to think it's planted the seed to something even more valuable.
But yeah...for any long term investment I will almost always pick a project with utility.
It can sometimes be a tricky task trying to find them

.