Yes, it's touch and go whether canards pay their way. They improve low speed handling... Consider a Concorde about to touch down; it was John Farley I think who described it as an upside-down flapped delta at that moment. All elevons up, forcing the TE down, and the nose up.
And consider T/O. Concorde's wing produces no lift until it is pitched to positive AoA on rotation. So just before that point the tyres are doing about 250mph (pretty much the limit of tyre technology) with all 185 tons of the aircraft's weight on them. Them the pilot pulls back to rotate, the elevons go up, forcing the TE down, and those stressed tyres get a big extra loading as they are forced into the tarmac as the aeroplane rotates. Canards would be very useful to raise the nose without the airframe puting that extra load on the tyres at rotation.
More efficient to have canards lifting the nose than elevons forcing the tail down. But the canards have to be retractable for supersonic cruise, and that means a lot of added weight. Not considered worth it on Concorde.
I think it is incorrect to assume a delta with canards indicates a poor aerodynamic design.