The bottling bucket helps in filling bottles, mixing in the sugar for carbonating in bottles, and it gets the beer off some of the trub when it is racked from the fermentor into the bottling bucket, keeping some stuff out of the bottles.
I just got a better bottle to try, I like the carboys because, for me, they are easier to seal airtight than a bucket, and I like to see what the beer is doing. I have a few glass ones that I use now, and I do meads and wines, so I rack and age more compared to beer. Also I have a hard time trusting buckets, just a personal thing.
As far as adding equipment, another bucket or carboy or better bottle, and a spout to make a bottling bucket would
be my suggestion. Maybe a hydrometer.