Now i checked back the finalized trxn details. It didn't charge me handling fee. My bad.
I keep thinking i was charged, probably because the last screen (before proceed to payment) show me the handling fee. If I recall correctly previous trxn were not like this, that time the screen showed waived fee (instead of 2%).
Thanks for head up. I went back to check trxn details, indeed no service charge.
You can try make a payment see got fee or not.

if straight use boost to make payment, elinking charge RM1 per transaction.
assuming reload from cc which has 5% cashback, and the payment amount using elinking is RM100

100 * 0.05 = RM5 from reloading into boost

if take mission in boost for making payment, (scan n pay?), reward is RM3 (example)

the cash back for making payment of RM100 is RM8 - RM1 = RM7
however, if the reloading cash into boost doesnt entitled any cash back, only got mission cash back, the cash back need to minus RM1 in elinking
which doesnt sound a good cash back in this scenario...
unless topup elinking app credit is also consider as "scan n pay" in boost, then can avoid the RM1 charge...
so, is the topup of elinking app credit using boost, consider as scan n pay or how?

the top up to app credit daily voucher is only once a day is it? Or every top up will get?

Also for TNB payment will I get voucher if pay more than 1 account in 1 day? Or only 1 voucher per day?

for the bold part, is it better get more coins in boost by reloading bigger amount, say RM200, or RM20 x 10 to get app credit in elinking?

well i gotten 400 coins for reloading RM200 ystdy...

no. not always.

Sill no use as you cant make the payment directly only  via Boost or Touch and Go e Wallet. MCO times where to go and pay via kiosk  maaaa

My point is elink can't do within the comfort of house sofa. Ebanking alone don't have any cashbacks