In an angled port or Conrad, the port is angled forward about 60 degrees in relation to the cheeks. The theory behind this according to one manufacturer is that it allows for better palate clearance. This seems somewhat counterintuitive, since the angle would actually bring the port up towards the palate. However, it keeps the port further forward in the horse’s mouth, where there may be more clearance in the palate.
In any case, it certainly takes more pressure off the center of the tongue, even when the bit is not engaged, so that should also make it more comfortable for the horse, and help transfer more pressure to the bars.