Mhhhhh, I'm a researcher in the field and I'd say it's a mostly inaccurate statement. The root-SIFT detectors and descriptors are still really good. If you try to match images in different conditions (day/night), then CNN based approaches are OK.
I would argue more that SIFT was valuable in introducing a new paradigm of feature extraction/matching. It is a staple of many computer vision courses. But yes the main algorithm I'm sure is quite (practically) performant as well
Which one were you thinking about?