I use the droplet side mostly using creating LEMP stacks.
Basically it allows you to spin up a say a webserver in about 20 seconds. Pick the image and you’ll get an IP address moments later
I use Forge before it so it handles things like repository deployment, let’s encrypt, puts your key on the server and gives you the connection details.
It’s been around ages but I still think it’s cool.
Has a few rivals like Vultr, Linode etc but it’s pretty much number one in its sector imo. There’s obviously AWS.
The only key threat to that side is the rise of scraping traditional servers and going serverless but it’s only rarely done in my experience.
There’s more to it than just droplets but that’s what I use it for.
Along with CloudFlare it’s a much needed tool.
The only other service like DigitalOcean would be Kinsta for Wordpress (which unfortunately a lot of clients still want). I’m sure they might IPO at some point too.