These are two fundamentally different processes. About the only thing they share is that they're both competitive processes important to academics.
Why does funding evaluation take so long? Think about the process from the perspective of a NSF program manager. Let's say you get 600-700 proposals for a single program (not an exaggeration). First thing you have to do is to deal with the logistics of partitioning proposals across your team of PMs on the program. Then work on classifying proposals into distinctive subgroups for review by panels with expertise on the specific subtopic (e.g. imagine the # of subareas included in a general call for computer security like SaTC). Then once you've got the dates, you need to solicit volunteer panelists or identify names, then filter for conflicts of interest across programs (i.e. did they submit a small SaTC proposal this cycle). Then you send out invites and hope they can accept and be there for a specific panel on a specific date. Repeat until you've got enough experts for each panel, and there are likely to be 30+ panels to organize (assuming an average of 20 proposals per panel).
Just the time to hold the panels will be significant. Each panel takes 2 days, and each PM can do at most 2 panels per week. You can maybe double up a bit, but you're still looking at 10+ weeks for the panels alone. Then process paperwork and aggregate results, deal w/ consistency issues, then make recommendations. Then wait for paperwork approving funding amounts. Then you're close to notifying the PIs.
Compare this to chairing a conference, where the PC selection, TPC meeting dates and logistics are all done way ahead of the paper submission dates. You know who will review which papers, who will be at the TPC meeting, and there is no further approval necessary once the PC chairs finalize decisions after the PC meeting. Having chaired a few conferences, I can tell you that the PC selection/invite process, and logistics of the PC meeting, can easily take up to 2-3 months. That alone accounts for most of the difference, not even considering post panel approval and funding paperwork.