????? My CC rebates 0.5% of my monthly spend to me.
I'll give you that (mine doesn't, as it happens, but it has other advantages**), although with qualifications. I think it costs retailers a fair amount to provide credit card use, and I expect your 0.5% rebate is eventually fed back into the prices you pay.
One could also argue that this rebate is an active incentive to spend, rather than to save, which may be good for the economy (so we are told, in these consumer-led-recovery times), but may not be so good for your personal wealth. I am sure that you are hard-headed and sensible enough not to be affected by this, but perhaps those less disciplined might be, perhaps at a subconscious level.
I need to carry only a small amount of cash. My statement is an excellent record of what I'm spending. It's handy for internet purchases (I use this more and more). If I refuelled the car in cash I'd spend all my life at ATMs.
I think you have missed part of my point then. Debit cards offer all the advantages of the above (with the exception of automatic cover on purchases (although my debit card provider offers a limited form of this)), so if debit cards had come before credit cards, the only additional advantage of the credit card would have been to get you into debt.
If I use my debit card the money comes straight out of my cheque account and I lose interest.
I'll give you that one as well, although again with qualifications. Although my current account doesn't pay any interest at the moment(**), it is linked to an e-saver that does, and it is a simple matter to swap money in and out, penalty-free, so the bulk of my ready-money goes into the e-saver until needed. Admittedly, the interest even on the e-saver is rubbish at the moment. However, before the near-zero-interest-rate policy kicked in, although both offered interest, the e-saver was better, so in practice, the interest on my current account was a negligible factor. OK, perhaps where large purchases are concerned, you may have a point.
If you use a credit card, even if you pay it off in full each month, you are still technically getting into debt, even if it is interest-free.
I suppose those who don't pay-off CC balance are subsidising others, but overall my CC seems like a good deal for me.
Of course they are subsidising others, but yes, on balance they are useful for those with the self-discipline to pay them off each month; whether they are actually a "good idea" though is moot.
(**Nationwide credit card and Nationwide Flexaccount current account. The latter was one of the first interest-paying current accounts, so it's a bit annoying that it now pays 0%, but c'est la vie. Advantage of both is that for the moment anyway, there are no transaction charges abroad. They said they were going to start passing on the Visa charges abroad, but I haven't seen this, even outside of Europe, so far, so still a good deal).
On another tack, when debit cards first came out, there was a TV advertisement popularising their use, featuring Denis Healey. For younger viewers, he was Defence Secretary and more famously Chancellor in the Labour governments of the 1960s and 1970s. The ad was done in quite an amusing way anyway, but the best bit was at the end, after he'd come out of a shop, and then walked up the street past a branch of Threshers. He looked to camera and made an amused/bemused/cheeky face.
This was a reference to the incident where the then Chancellor, Norman Lamont had apparently failed to make his credit card payment, which he had used for substantial purchases from Threshers. Of course it was in reality a trivial event, but the press played it up for all they were worth, as they are wont to do. Anyway, that bit of the ad was hilarious at the time, although people might not remember now. Unfortunately, someone complained, and they had to edit that bit out of it! :-(