I'm pretty sure somebody already asked that but what is the difference between Itch's and GameJolt's goals?
1) As a developer working on a soon to be announced game I think itch.io has more potential for not just the developer but customers. In steam, game jolt you have to go outside of the site where you found the game to purchase merchandise and support the developer in other ways, while on other sites such as steam you have to look for it and might end up not really supporting the developer.
2) Also you have better access to the developer and can truly be heard. I believe that itch.io is a hit away from being number 2, it's just that many developers falsely believe that they will build a fanbase here and abandon itch.io and they will follow them on steam. Itch.io is a one stop shop, it just needs a hit be it a game, novel, comic book, merchandise, it just needs a loyal developer. Steam has become so big and oversaturated that they no longer try and are falling without even noticing.
And it's to late to change the course, with all of the money steam makes they should be publishing more steam original games, films you name it instead they are just hosting reskined or lazy made games. Itch.io will make it soon mark my words to the top.
I have to agree that workflow with itch.io is more seamless but I didn't see using GameJolt as that much complicated. You're right, I forgot to mention that itch.io is more catered to a host of different items aside from games whereas GameJolt is purely for games. I'll add that on my list above, thanks!