Another issue with the Land Rover handbrake being on the propshaft, was people who applied it while still moving. Not unknown to break the half-shaft splines as the momentum of the vehicle kept the wheels turning as the propshaft stopped.
I've never been a fan of parking in gear. Especially as 'official' advice is to put in a forward gear when facing uphill, and reverse when facing downhill. Why would engine compressin be greater when the engine was running in reverse? Nonsense. But, it might cause the timing belt or chain to jump a tooth or several. Whilst compression will leak away, piston to valve contact would hold it on any hill.
Right from my first day working in a garage, I've felt uncomfortable about parking in gear. How could the garage, responsible for the vehicle operation/safety, declare their work unfit, by parking in gear. If the handbrake is unreliable, fix it. (Or move to the fens)
Electric parking brakes make features like Hill Hold and Auto Hold easier, using the park brake mechanism, rather than hydraulic pressure. As said above, Hill Hold only holds for a few seconds, which many owners/drivers do not appreciate. They stop, leave their foot on the brake, like they do every time they stop, (dazzling us in the dark), then release as they alight. As they walk away, so does the car. And then they blame the automated brake system, declaring they of course applied the brake. This has caught out a few supermarket drivers, and a runaway Sprinter van is not to be welcomed. A company edict has declared must park in gear. I demonstrate how the gear will not hold it. It takes about 5-8 seconds to roll over the first compression, and bumping into the next reduces that time with each movement. With such large wheels/tyres, resting against the kerb hardly works either, as it just rolls up over it.