Relaxation & idleness are not the same thing.
It’s important to make time to relax, both mentally, physically, and spiritually.
To actually schedule relaxation time onto your calendar as a priority, each day.
Idleness, on the other hand is just milling around, doing nothing particular. You might engage in some task, such as checking email, watching tv, etc; but none of those tasks is actually a top priority as it relates to your values and/or creating value.
If anything, idleness is a form a stalling and avoiding what’s really important.
Relaxation, that’s making sure you are in the best possible condition to do what is important.