We currently don't have a need for ILs in SRC because they already exist over at https://board.portal2.sr/changelog (AKA the CM Boards). Previously the SRC boards did have Individual Levels; they were left entirely unused and empty by the community. Due to that we decided to use the IL section of SRC for Chapter runs. Although the chapter runs had a slow start, they are slowly starting to accrue popularity throughout our community.

The closest we would ever get to bringing Portal 2 ILs back to SRC would be a bot which manually moves, approves, and links proof from the CM Boards to SRC. The positives of this would likely be that the popularity of Portal 2 would be more accurately reflected on SRC, it would function as a history backup should the database ever be lost for the CM Boards, and of course it would make world record histories more widely available to the general speedrunning public.

Unfortunately, we would never accept runs being submitted from SRC to the CM Boards because SRC doesn't have a feature which would allow the user to upload their demos directly to the site. Without this crucial feature it would become nearly impossible to ensure that all demos remain available for all users at all times, that all demos are quickly and easily accessible by moderators to verify at any time in particular, and of course that we could easily backup/move/modify demos as is sometimes necessary with a game like ours.

I really do recommend using the CM Boards for your Portal 2 IL submissions. They really are a convenient way to speedrun the game if for no other reason than the fact that they have autosubmit!

I'll be locking this thread so that the answer to this question/request is easily available to anyone looking.