Find your niche.
I used to be obsessed with that little feature! I was in for the flutes, of course. Although I don't think I ever got to trade in enough ash for more that two flutes, I still oddly enjoyed collecting the ash. I remember trying to step through all the soot covered tall grass tiles in a single continuous line of movement and just having fun. I think back then I also tried to get one of those cheap decorations for your secret base (because I loved that feature back then for some reason) and felt ripped off right after purchasing, haha. But I'm pretty sure I never saved up enough for the Pretty Desk.
I love how useful the flutes were in HeartGold so I suppose I should thank this feature for being responsible for their creation. It gets tedious after a while, though. Especially when you get older and try it out again, apparently.