It would have been perfectly possible - not to mention obviously better - to make people actually write what they meant when defining the new type and this has

It would have been perfectly possible - not to mention obviously better - to make people actually write what they meant when defining the new type and this has no impact on the dubious priority of being able to make your own int type by gifiting your type implicit conversions in use if that's what you want which it often is not. This is just another thing on the deep pile of wrong defaults in C++.