I think this system has to be designed for some users who will never be online. Think of villages where there is no internet access yet (only 8% of Eritrea has access to the internet for example!). Hence there can't be a 'if you don't log in for 7 days you lose your money' mode.
Let me clarify: if you have you device with you (didn't lose the device) and you didn't make contact with another online device for more than cool-off period, your device tokens won't be refreshed and they will expire and become unspendable. You don't lose that money – it is still in your account and will be available for you spend as soon as you go online. The "lose your money" scenario is only if you lose your device and someone finds your device and spends the money on the device within the cool-off period. It is equivalent to losing your cash wallet and someone else spending your cash. Except in case of cash, that stolen/found cash is lost forever and is valid to be spent by the thief/finder forever whereas in this case there is a small time-window after which you automatically don't actually lose your money!