Just found out about experimental Reader Mode on Chrome and was anxious to try it on my Android tablet (Galaxy Tab Pro 10.1). I don't get the toolbar button either, but on my phone (Moto X) it works as expected. An old Motorola Xoom tablet exhibits the same behavior. Wonder why they disable this feature on tablets...

Just as the title says, I enabled reader mode under chrome://flags on my tablet (Galaxy Tab S 8.4) but the toolbar button to use it doesn't seem to show up on sites where it should be available. Works on my phone though.

Edit: accessing the reading mode directly through chrome://dom-distiller seems to work perfectly, so it's just a button problem?

Reader mode on Chrome for Android not working on tablet?