How do conference proceedings add to academic prestige?
I don't think there is any TCS conference that would be a fast track to a permanent job.

STOC, FOCS, and SODA are the most competitive conferences, and papers in those will certainly look very good in your CV, but just one paper won't help that much with the career. To really stand out, you will need something more than that (say, lots of papers in STOC, FOCS, and SODA).