has to be Barclaycard Platinum, only because the colour and the o% interest free to transfer existing balance onto it and pay it off without occurring more interest.
But also as the card is easier to use via the app and the way that it can be switched on or off if it is temp lost or even misplaced outdoors, the app can instantly block all use of further transactions if found and contactless attempts were made.
Could also, before the law change, decide to switch off certain types of transactions i.e., shopping, online, gambling etc, which i find useful, as well as setting the limit on it, having this via the app is half the battle.
I had other which were terrible, most notably Newday Amazon, which were a nightmare to manage at the start, although got a little better, but canned them after paying it off.