Today usury means charging an excessive interest....the older versions indicated any interest...
Of course if I had money and I could use my money to say buy a business and generate an income, or buy some land and improve it for profit, or buy some seed and plant and reap later....
or my option was to lend you that money and you return it a year or two later at zero interest....
hmmmm hard to decide isn't it?
Without the ability to charge interest on a loan, no loans would be made...
The rules were probably made, as most are to protect the public from unscrupulous dealers...and instill savings, and folks not getting in over their heads...not that there isn't any validity in this.