Do we still need to convert colorimetry of DVD source in vapoursynth?

[lansing]

I have this confusion on the colormatrix filter in avisynth for years now. According to its documentation, the reason for its creation was that commercial mpeg2-encoded dvd were encoded using rec709, while the old avisynth was using rec601. So to correctly display the color in avisynth, it has to convert the dvd color to rec601. From my understand, this was a workaround for avisynth's inability to correctly display rec709?

But then in this documentation, it was saying a complete different thing and usage of the filter:
http://avisynth.nl/index.php/Colorimetry

In general, it is safe to assume that Rec.601 is used for Standard Definition content and Rec.709 for High Definition content upon playback

What??

And then what about vapoursynth? Do we still need to do this conversion? I'm so confuse.