New rule forcing long-standing clients to log onto ebucks website now in order to claim rewards- for whose benefit?

I have banked with FNB for over 15 years and collected ebucks every month for several year, no problem. Some months ago I received and random communication with no rational explanation given that in future can't claim my ebucks rewards unless I log onto the ebucks webiste once a month. Why? To waste my time forcefully exposing me to advertising or deals I don't want? How does this serve me as a customer? Now I get messages clogging my whatspp taunting me saying IF I had logged onto the website I would have got R x in rewards. Thanks for nothing. If I qualified for these rewards for years without logging onto the ebucks website why I am being forced to do so now? Give me one good reason WHY- explain the value to ME of having to log on. I see it as co-ersion and exploitation,not beneficial customer service .