For people who are missing your second link: youtube-dl is a video downloader, and it works on far, far more than just YouTube.
The benefits: you download videos at your discretion and preference. You can archive them if you want (I do this largely for documentary / lecture videos), and play them back locally using the video player of your preference. I generally prefer either mplayer or xine, both offer keyboard controls over playback, vastly better rewind / forward control than YouTube's default player (or anyone else's for that matter), consistent video controls for all videos, and the ability to speed up (I run most straight presentation videos at 120 - 160% of normal) or slow down (things going boom) videos as desired.
Embedded players are OK for getting a quick sample of something or very brief content, but not for serious viewing.
FF/RW problems may be your ISP and not YT. TWC is notorious for routing YT through its own servers and it's terrible; others may be just as bad. https://news.ycombinator.com/item?id=5276772
The benefits: you download videos at your discretion and preference. You can archive them if you want (I do this largely for documentary / lecture videos), and play them back locally using the video player of your preference. I generally prefer either mplayer or xine, both offer keyboard controls over playback, vastly better rewind / forward control than YouTube's default player (or anyone else's for that matter), consistent video controls for all videos, and the ability to speed up (I run most straight presentation videos at 120 - 160% of normal) or slow down (things going boom) videos as desired.
Embedded players are OK for getting a quick sample of something or very brief content, but not for serious viewing.