Whether you experience installation difficulties probably depends on what kind of machine you have. A standard laptop with one drive? No problem, judging from responses here. Well, good for you!
I have a machine with multiple drives. I also have an Nvidia graphics card. Both these circumstances were creating problems.
Firstly: The installation failed for me 2-3 times with "Grub fatal installation error". No further info or details. Eventually I googled it, realised what it was, and that I'd have to unplug all but one drive for the installation to work.
Second issue: Monitor completely failed to recognise graphics card and displayed nothing at all on the monitor when booting in Mint. Fortunately my CPU has built in graphics, I patched in a monitor there, and discovered that I had yet another crash - Cinammon crashed, reverting to very restricted "fallback mode".
What if I'd have no other graphics? What if I was a non-technical user who could not guess at what the problem was?
And even for me, this was challenging. Remember - I was brand new, so did not know anything about what Cinnamon is, and as far as I am concerned I have a standard graphics card, picked up off the shelf at PC World.
I realised that removing the physically graphics card prevented the crash in cinammon and set about researching how to resolve the Nvidia issue. I had to figure out that appropriate drivers had to be obtained through the software manager. Reboot the PC with the card back in. Hurrah, no longer crashing, but cannot get the resolution I want. That's essentially where I still am with that.
Now: Would your mother have managed this? What about your non-technical neighbour, wife or friend? How about even a "superuser" in your office?
If my experiences are not a threshold to uptake of Linux Mint, I don't know what is!
Yes - nobody is denying that for an off-the-shelf laptop or basic PC the installation is probably painless. Good for you!
But not everybody has that type of machine.
- In lots of countries outside Western Europe and North America, most people are on PCs that were built by a local shop using spare parts, i.e. "recycled" machines, or machines put together from new components, due to the fact that the components are made locally and are cheap there.
- Many Western kids have "gaming rigs" that they may have tinkered a bit with themselves, or that was built by some small supplier of this type of PCs. These kids are not necessarily technical enough for serious troubleshooting in a scenario like this.
- Some people had their PC or laptop sent for repairs to a local shop which replaced a few components with non-standard bits. That's all it takes for the installation process to fall over as far as I can tell. And the user being non-technical doesn't even know their machine is no longer standard.