It think most people here who complain are people with Explorer and / or Edge, and they still need to pay for a full time Visa / MC for places which does not take AmEx. If I only have Edge card, I may also cancel the Edge card, and consolidate to something like St George Amplify Signature for SQ and be done with it.
Be careful when you do this, when you could end up cutting up your future earning opportunities, especially when you have a Platinum charge which gives you heaps of free cards. I encountered 2 such occasions.
1: 15+ years ago, I got an invite to get a fully featured Diners, free for life, as I was a Citi credit card holder. It was not the additional card like what Citi is doing now, but the whole separate shebang. I didn't take one, so now I miss out on all the lounge access.
2: 2 years ago, I applied for some AmEx card. AmEx told me that I needed to cancel one of my existing AmEx cards as I had too many. It was either cancel 1 existing card and get approve for this new card, or no new card. I had and still do have $395 for Reserve + Edge + gold charge, I could have been greedy and taken the new card for sign up bonus, and cancel the Gold and Reserve, so I would only have to pay $200 for the Edge card and I get $1 = SQ 1 plus bonus supermarket spends, plus the sign up bonus. Well, if I was greedy for that short term gain 2 years ago, I would be left with the Edge card now, and crying.