I have made many graphic organizers over the years in school. They have many purposes and they are a great way to organize your thoughts, especially before diving into an essay. I have always created my graphic organizers by putting pen to paper, it had never even occurred to me that you can make them digitally online. It was a different concept that most definitely has it's advantages.
Creating a graphic organizer digitally is not all that different then making one by hand. Honestly, the biggest difference is one is digital and one if hand written. I can't even make the argument that writing one on paper is faster because you still have to dig or your journal and your pencil and with the digital one you have to dig out your computer and pull up the website that you choose to you use.
In my class with my students, I will give them the option to either make a digital graphic organizer or a paper one. I won't force them to use one over the other. I will be using graphic organizers to brainstorm for essays and all other types of projects. Like a compare and contrast chart, cause and effect, time lines, mind maps, concept maps, etc.
The biggest concern I have with using a digital graphic organizer over hand writing one, would be what if the computer crashes and the student has not saved what they are working on. Then all of their work is just gone. Another concern would be "do my students have access to this technology outside of school"?