Lol, had the same question so I went to test out of curiosity.
So far what I know is:
1) SimplyGo is supposed to be this new system they are transitioning into so that all forms of payment such as ez-link, bank cards, mobile devices linked for contactless payment etc are combined into one system. 1 main benefit I think is you can use your bank card to tap the ez-link even without sign up or activation. I tried on a DBS debit card but on their site it says all cards can.
2) If you using an ezlink card now, you can go 'upgrade' to the Simplygo version via the ez-link topup terminal at MRTs and bus stations. However, this also means it will have some changes:
- To encourage people to do so, they hire promoter to help you 'upgrade' and give you $2 rebate immediately. I did exactly that and is not bad, $2 free money.
- However, please note that with that, everytime you tap the ez-link, it will show SimplyGo instead of info like the amount deducted & ez-link balance remaining. For that, you have to download the ez-link app which will bump a notification everytime you tap out.
- Apparently also after the transition to SimplyGo, if your ezlink card expires, apparently you can just transfer it to another card via their app but I haven't tried so not sure what's the diff as when we go to MRT control station to do this.
3) other than all that, SimplyGo has no other visible benefit other than checking your trip history in more detail as compared to the Ez-link app.
That's all I know.