Actually though. I've asked it questions about impossible things related to technology and it's even gone as far to make up things for features that don't exist.
In one case I asked it once if it was possible to have Kafka partitions shared across topics (currently impossible per design) and it was confidently incorrect, even gave me a made up command line for how to achieve what I asked.
Depends on what you're looking for exactly. Great for casual play. This was released before modern changes that introduced some rule changes and the "new" Link summoning mechanic. There's a rereleased version with Links called "Legacy of the Duelist : Link Evolution", which includes a lot of the content here and it's only $10, so I'd say it's not worth it, and just get Link Evolution instead.
Compared to Master Duel, it's a bit outdated as MD is still running and is constantly updated. So there's no new cards since release, same with Link Evolution.
Compared to Duel Links, DL is based on the same fundamentals as regular YuGiOh but with some major changes like skills, 3 main monster and spell and trap zones, along with different deck sizes. Not exactly comparable imo, but again depends on what you're looking for.