After a while you earn the right to decorate select areas of the town yourself with your own furnishings and styling. Is there any reward for doing this?
Could I just remove everything from those lots to sell them (because greedy) and be fine?
Decorating the town appears to be mostly fluff, but according to a blog entry by Marie "the Crocheter" placing certain combinations of decorations (called edit combos) about town will gain you certain benefits. If I'm reading Google Translate's rendition of the Japanese Wiki then the possible benefits include better relations with the villagers, an increase in selling prices with the trade vendors, and a decrease in prices when buying from them. It appears you need to unlock at least three different locations in town before you can make any of the edit combos.
There are also edit combos that apply to your farm and at least one in your home. I believe the TV gives hints about edit combos so there's a non-spoiler way to figure out at least some of them without extensive trial-and-error.