Would be good for developers who need to port something to Linux but don't want to go through the hassle of setting up a dedicated instance themselves .. build-servers that need a full Linux setup, etc.

Might be good for folks who have very slow computers, or non-usable machines (iPads/tablets/phones/etc.) who nevertheless still need access to a Linux environment for school or work, or even just for the fun of learning Linux for the first time without much hassle.

Its certainly easier to use/setup an instance than some of the other options out there, although things seem to be pretty competitive in this space .. so who knows how long icebergs.io is going to be around.

I've bought a basic plan, anyway .. good for me to have my co-developers using this to build our project code without requiring a big fuss with setting up a PC/VM-instance/whatever...

In short: it can be used to do whatever you might like to do with a Linux workstation. So: quite powerful, then ..

If you are porting something to linux surely you will want to test it on a real VM at least? Those are pretty trivial to set up and are free...

This is a real VM. The likelihood that if it runs on here, it'll run on a 'real Ubuntu instance' is quite high.

But why one would pay for a VM as a SAS when you can install one for free in a just a few minutes on your own machine?

So you suggest this is a good use-case because you can run Linux in a recent Firefox on an old machine better than you can run it natively?!

Have you run a recent Firefox on an old machine for that matter?