Earlier quoted context omitted.
What’s the benefit of doing that please?
Most engine reworks like that (Doom, Age of Empires, Heroes III, etc) offer significantly improved performance and scaling for modern computers. There are often other enhancements, too, including native support for Mac, Linux, etc.
Not disputing that engine replacements / source ports can be great (I work on one myself) but it's weird that there are three replies that sidestep the actual question: What does this particular engine replacement add over vanilla GoldSrc?