A decent collection has specific pieces that tend to be very unique (especially as a whole). If you shared this elsewhere, whether online, with your tech, or your best friend, you have just identified yourself. Do I know who you are? No. Does someone else? Maybe, depending on how well you have safeguarded your privacy.
When you compare this to there being no upside, it is a dumb thing to do.
Any time you provide enough data to link your various online and real life personas, you risk your privacy.