Since here I am a bit more anonymous I can share on steemit stuff I wouldnt share on facebook. As I use Facebook only to keep in touch with friends and family and post on of those "look at what beatiful beach I am" pictures.
For people who promote their content on Facebook it is a different story for sure, but there I have no experience to talk about it.
As I think they still can co-exist as steemit is about sharing ideas, stories etc and facebook has more of a personal touch to me, it is still a business and of course if you promote a potent competitor on their site they will not be happy about it and it is also their right imo as they want to protect their company of course.
Things will get really interesting if steemit will also go to a more personal level as for now it is more like a better reddit imo.
Every company is gonna offend by its competitor, i mean look at YouTube when you post some link from YouTube Facebook will only show it to a few people even if you have millions of likes or followers, the same will be happening to steemit even if they allowed it on their site in the first place, Facebook want to control the whole internet and also want to destroy YouTube as they recently acquired the services of big Hollywood studios to make original shows which will cost Facebook 30 million per episode, we can criticize YouTube but at-least they are paying the creators something, on the other hand Facebook is not paying the creators a penny @firepower
What's more frustrating is when I try to show people how a video I share through YouTube won't get watched but a video I share through Facebook gets all kinds of pay and they either don't believe me or don't care T_T The only way around it is to do as the OP does and share an image with a URL and now it seems even that is under fire :-o