hi, it is to cycle through presets without bending down. very useful, last week we did Remember the time straight into Material girl (preset 1 into preset 2) life saver!
I like the AMT very much, very capable for its size. warms up the tone quite nicely, can even provide low gain tube hair. loads of options available via switches too. Alembic tube pre based according to description, but I haven’t tried the real deal for comparison.