Sizing up sends
Plugin effects make it easy to mix processed and dry signals, so effects such as parallel compression can usually be whipped up without a bus. This is convenient, sure, but there are still tons of reasons to take your time and make full use of send and return setups.
The most obvious reason for using auxes is that the effect you’ve used can be processed separately using your choice of plugins, without touching the dry signal. This is ideal for tasks like removing the boomy sub frequencies from a drum reverb, or applying compression to rein in a wild delay line, for example.
Another use of sends is to apply stereo processing such as reverb, chorus or phasing to a mono signal. If you insert a stereo plugin on a mono channel in most DAWs, the output signal will be summed to mono – but with a stereo send, you’re good to go!