Not necessarily better. Just another option to consider. WET/DRY mixes in the air, and applies here for ‘historical accuracy’. STEREO allows you to craft the mix spread internally, so it’s compact & versatile.
For that matter – one H9 in/out cabling will sum everything going on back to mono. In some cases, there’s advantages to going into one H9 in mono, sending ‘stereo’ to the next H9 (or two), then summing back to mono again. They all have their charms (and specific uses). Go with what you’ve got.