Yes these talismatic symbols meanings have been lost in time it seems. Perhaps it’s pointless to seek to rationalize them too much as they are based on superstitions. I think palindromes and repeated numbers were considered particularly strong. These were tough times and people desperately sought solace where they could.
I found this which might be relevant too:
http://biblehub.com/exodus/14-14.htm
The LORD will fight for you; you need only to be still."