The writer is trying to equate mpesa balances to e-money units (think something like bonga points. Such that when you load Ksh. 1000 to your Mpesa, you get "1000 points" which you can then transfer and use to purchase items. If at anyone time you with to redeem, you get Ksh 1 for every 1 e-unit money.
Its an interesting read, especially while arguing whether safcon can borrow from the mpesa bank.