Using a bowden adaptor is a very tidy solution for bowden based 3D printers. A bowden adaptor easily converts a direct drive extruder, that normally accepts a groovemount hotend, into a bowden extruder. The E3D bowden adaptor mounts like a hotend, but accepts PTFE Tubing, just like a pneumatic coupler.
Using one of these is a neater solution than a pneumatic coupler, because you no longer have to force thread a coupler into a printed mount. Instead you can use your existing extruder setup.