Prob people who prefer old card take longer to see their balance and do some mental calculation if it's correct. Hold up the queue. Then complain why others take so long to get down after tapping. If its wrong even worse, they try to complain to bus driver as if driver can do anything and refund them... Then hold up the bus even longer.
They also like to spend longer queuing up for disputes at the Transitlink offices.... Then complain why people at the booth take so long to explain to the CSO because they cannot properly explain what bus they take, from where to where, and what time etc.
As people grow older, they become forgetful, these apps are supposed to help them remember and keep track of their expenditure when travelling. It can also help to keep track of whether you are within the 2 hours of doing transfers and getting the discounts. Unless you tell me people can memorise exactly what time they board the bus. Or they can rember how much balance they have in their card which they use couple of weeks ago. Or worst, they keep multiple cards and forget how much each card have and which ones to top up. But they prob don't mind either trying each card out in the bus (and holding up the queue) or making their way to the ATM or train station to check their balance. Pretty much how they don't mind queuing to update their bank books, which they can sometimes misplace.
Actually the excuse that the elderly wouldn't know is pretty lame, pretty much most of the elderly have Senior Concession Cards (60 years and above) which are NOT required to update. Unless you're a foreigner who don't qualify.
The only issue with the system is whether it can cope with the huge influx of new users by the 1st of June. As it is, the system is fine with the current number of users but how will their servers and network cope with a million or more new transactions a day.