There's nothing worse than getting stuck in traffic going up a slick hill in a Midwest winter with a manual transmission. Your car goes backward!
In an old manual transmission, that's true. Modern cars have anti roll back systems. But also, use the hand brake.
Can't you use the clutch and foot brake smoothly enough to take off on a hill? Even a slippery one? Hand in your manual transmission driver's licence!
[Tidbit: where I live drivers are issued with different licences for manual and automatic cars. You have to pass the test in a manual car for that licence, otherwise you can only drive automatic cars.]