I do this primarily to maintain the original aspect ratio since Instagram stubbornly insists everything be square. That's first. But secondarily I find it feel like my film days when I would matte photos after developing them. The end product feels more finished to me and overall more pleasing. It's like that little drizzle of sauce on the plate at a fine restaurant. It may not have any real function (or here maybe it does) but it's for the aesthetics.
I do this primarily to maintain the original aspect ratio since Instagram stubbornly insists everything be square. That's first. But secondarily I find it feel like my film days when I would matte photos after developing them. The end product feels more finished to me and overall more pleasing. It's like that little drizzle of sauce on the plate at a fine restaurant. It may not have any real function (or here maybe it does) but it's for the aesthetics.