I feel like the various bits and pieces you find in various quests will add up to something in the future - Amelia, Lovisa, and Eliana's quests being notable examples. I hope so anyway.I blew something like 1.7 mil on that whole set-up and I'm not sure what I got out of it outside a relatively paltry income and some flowers I guess. I was just thrilled to find out I was expected to shovel the shit too, not to mention retrieve it from rather hazardous locales. I'm hoping Grim has more planned for the Gardens, I did like the idea of investing in green growing things, perhaps with the appropriate scientific knowledge you could make a big discovery or something?
For the present.... yeah, not impressed. A higher initial outlay should result in a SHORTER time to break even on an investment. To add insult to injury neither your accountants nor Rebecca appear to boost Toshi income.