Agree totally with the "... lead well-meaning astray". My wife is one of those perenially hopeful ones, but her optimism has kept her and me sane for fifty years. Usually I can share with her logic that opens her eyes. This time is different. Things have gotten so dire (seemingly) that she is clinging on to the hopium even beyond my ability to open her perception to the bigger picture. But God has helped me to console her after these "predictions" don't pan out, and He will again.

I don't think necessarily that those using the gematria are intentionally being deceptive... they're just using a tool and deceiving themselves. I'm much more suspicious of the tool itself since I was a computer programmer and can usually spot inherent sources of error when the code was designed. Ferguson's pandemic model and IPCC climate models come to mind. All are tools that Satan can use to his own purpose of deceiving us.

Thus the need for the full armor of God.