The driver has to actively compensate for these variations so the car is less relaxing to drive. The driver cannot correct for a fall in engine revs and loss of torque if the throttle is already wide open, except by changing into a lower gear. This can be a safety matter on a steep trail. If you start up a steep hill in too high a gear, or have to slow down due to rocks, for example, the engine may fall below maximum-torque rpm and be unable to recover from a downwards spiral. Changing gear looses more speed and traction may be lost as the clutch engages.
Inaction leads to a stalled engine and a restart on a dangerous slope.
These risks are minimized if maximum torque is attained at low engine revs. So, if you are into racing, particularly Formula One racing, you want an engine with the highest possible power output and this is best achieved by generating maximum power at very high rpm. Such engines also tend to generate maximum torque at very high rpm and are inflexible and difficult to drive - but that is what the aces are paid for.