One common motivation I've seen people say for uploading submissions onto weasyl, is that people go to where the content is. But to make it easier there's an extension for Chrome that allows you to cross-post quicker (I don't know how to use it as I'm a Firefoxfag) But brief history of the furry fandom is that a decade ago when Deviant Art started discouraging Furry Art, people took off to SheazyArt, SA decided it didn't want to be nicknamed SleazyArt banned Adult Art, which lead to the Creation of Furnation and Furaffinity, when FurAffinity Banned Cub-Art Permanetly (And Sonic Art Temporality) it lead to Inkbunny kicking off. Given the lack of Controversy surround SoFurry it's often termed as the most boring site to use, despite it does have an achievement system.

If you do decide to crosspost, you can think of it as an investment and reaching out to other people who may be exclusive to one site, as not everyone will fall in the overlap on a Venn-Diagram given the reasons people have decided upon to leave more recently. You don't need to upload all your submissions onto both sites, but keep in mind that Weasyl will only display your most recent THREE submissions on the front page (This is really to give other people the chance for exposure) so you can literally take your time with this to reduce the effort you need to exert into a daily task and still get a maximum exposure as you upload each day.