Basic banking in Belgium is much worse. What you are paying annually in Portugal for basic banking is a /monthly/ cost in Belgium.
Then the issue is not the cheques or them being suppressed. It's Belgian legislators being morons and/or assholes. That's what you should protest against because no paper cheque on earth will make your politicians suddenly more competent or less of an asshole. Note that we our own incompetent assholes here in France too, not pointing any blaming finger toward Belgium ;)
Also don't forget the coming Digital Euro. For a while it will be optional, look how practical that is come try it, but their objective is most certainly to get rid of any form of cash, aka physical money.