[ubuntu] Power off this disk – data integrity

When I connect a thumb (flash) drive to my computer, it shows up in the Nautilus/Files app with a little eject button next to it. When I click the eject button, a notice appears saying it is safe to pull out the thumb drive. But even after this safe to pull out notice appears, some of my thumb drives still show a solid light indicating that the drive is receiving power. If I open the “Disks” app and select the entry for the thumb drive, there is a Power-Icon displayed that says this when I hover the mouse over it: “Power off this disk”.

When I click “Power off this disk” the glowing light on the thumb drive disappears and the thumb drive no longer appears in the “Disks” list.

Should I ALWAYS “power off this disk” before pulling out a thumb drive? Are there some instances where I should “power off this disk” before pulling the thumb drive but most of the time it’s not necessary?

I want to avoid any chance of date corruption or loss before pulling out the thumb drive. [I use it for backups].

What is the point/function of “Power off this disk” if it is safe to pull out the drive after clicking the “eject” button?