Hi,
just a bit about correct terminology:
You talk about "latch". A latch has a data input and a control input. The control input decides whether the latch is in transparent mode (inactive) or freezes the data. The latch control input is level sensitive.
If you don´t need the latch function, simply tie the control input to "transparent" state.
But the HC595 has a "D-Type flip flop". The control input is edge triggered, thus it needs "edges" to transmit the data to the output. There is no "transparent" mode on D-FFs.
Using latch or D-FF on shift registers makes sense. If you don´t use them, then you see the data rippeling through the shift registers. Usually you don´t want this.
Klaus