trisquel in a virtualbox

>come to think of it, trisquel is running on the proprietary nvidia driver installed on the ubuntu host when I run it in a virtualbox, isn't it ?

This is correct.

Welcome to Trisquel !

IMO the simplest approach to test Trisquel on true hardware, is the installation to a simeple USB stick. Most modern motherboards support booting straight from USB and technically there is no difference between a HDD and an USB stick.

I run my first Trisquel 5.5 installation from a 16GB USB stick without issues.

There are two things to be concerned about:

1. Is your operating system spying on you

With Ubuntu the answer is it is. With Microsoft Windows the answer is it is. With Mac I'm not sure although the answer is almost certainly yes (Apple's got everything tied and integrated at such a point there is spying going on all over the place).

2. The next question is how quickly does one receive patches / security updates from the distributor.

Microsoft Windows has a cycle. They generally don't release security updates as they become available. Rather they hold them until a particular day. I believe this is called patch Tuesday. It's not good from a security practice. They occasionally release patches out of turn when things have gotten really bad (ie there are exploits, infections, in the wild, etc).

I'm unsure about Apple's security policy (if they even have one) although I do know that they often take a very long time to fix stuff. In some instances they simply disable the technology altogether.

Trisquel's pretty small so the security updates for certain packages take a bit longer. Maybe not quite as bad as Microsoft although certainly longer than Ubuntu, Debian, and various other distributions.

Debian is probably the best solution as far as the core being purely free software (although they do not meet FSF distribution recommendations / requirements for certification) and prompt release of security updates when new patches are available. Trisquel is easier in some ways than Debian. The one thing to be concerned about with Debian is they will instruct you to install non-free software that could be a security risk. Trisquel complies with FSF certification requirements and so you can be confident that you won't be advised to install non-free software if some piece of hardware doesn't work or software is broken.

Most likely your biggest concern is probably the invasion of privacy rather than an attack on your system. I'd say Trisquel is also easier to use. It's based off Ubuntu, has a clean user interface, clear download (not a thousand unclear ways / versions you can download), etc.

Burning an ISO has worked fine for me for years! I find it easier than getting a 100 pack of USB flash drives- in comparison or having to wipe/reload. USB flash drives generally have a limited life span. Particularly when you use them a lot/heavily. While a lot of people play around with USB booting I've actually used USB for booting in a heavy fashion (six months of daily use- and heavily- hours and hours and hours) and have yet to find a solution that really works well. Even with read only partitions, etc. Now if you don't apply security updates it will probably work fine. But start booting in a write mode to temporarily apply every security update that becomes available and it's game over.