Why don't these machines have buttons?
For home coffee machines please avoid buttons. The primary reason for this is that for truly great espresso you need to extract by colour, not by time or by volume. This may sound tricky but don't be concerned at all - you can read about extracting by colour on my Training Page.
A secondary reason is that buttons takes away that hands-on manual coffee machine feeling. Driving a powerful manual Italian coffee machine is a lot of fun - like driving a V8 !!!