It also serves to confuse the crap out of passersby when they see your taillights on.
I once had a lady looking way too interested in my bike in a parkade.
She was looking at the back, then scouring the bars and instrument cluster, and leaning all over looking for something.
As I walked up to her, I asked what she was doing, and she pointed out that my taillights were on and she'd been looking for the switch to turn them off.
I hadn't realized that I'd turned the key to P either.
I think I read, in the Owner's manual, something about increasing visibility in some parking situations.
As to the battery removal, no, it doesn't really get easier. What I did was install a charging pigtail when I put the battery back in. That way, other than for winterizing, the battery doesn't have to come out anymore. I agree, it's a pain, especially if you have a full tank and no helper.