The importance of their work and philosophy should not be underestimated. And the Libre principles are more important now than ever before.
Libre says that the user is king and the system must never be used to oppress the user. Rather the user must have fun control over the system and it's code.
In a time where all operating systems not desktop and mobile are abusing users, taking their data and locking away the code from them accessing it, we must remember and practice the libre principles.
Use Linux on the desktop and Android on your phone. Especially custom android if you can, but even stock android still gives you a lot of control and 3rd party apps exist which protect your data.
On iPhone you have no such protection and are totally under the control and whim of apple.