Hey there 
Being a local guide and an avid traveler gives “local” guidance a new meaning. For me, if I stay somewhere, I always try to update maps around me, so that other travelers know about the interesting spots I’ve found. Or just take pictures and rate already existing locations. I’m quite often in Chiang Mai (lived there, love it) and quite a lot of spots or small businesses are not on Google maps yet. Adding them helps them and improves Google maps at the same time.
I rely a lot on reviews on Maps, so I guess that’s the main reason that I love writing reviews and taking pictures of the visited places the most. In my opinion, Maps is a really good way to get an honest first impression of a spot you might consider visiting while traveling.
Fun story - I’ve been up in the mountains in this beautiful resort about 40 mintes from Chiang Mai:
Looks amazing, right? Well, unfortunately no one tells you that the water is ice cold. No seriously - ICE cold. Due to the filter and constant water circulation, there’s no time for the water to heat up. So you practically freeze to death. Well, maybe not that extrem but still. Anyway, that was a point my review made sure to empathize. Now you can go there prepared and maybe not be too disappointed that you won’t be swimming in there and just taking some Instagram Pics.
So that’s why I love sharing reviews - to give everyone a good chance to explore prepared.