I think it is purely semantics. A verbal instruction is still a task the same way as an online written one is it just isn't called such. The reason why online tasks may seem more detailed and involved is because you have to write out more instructions to make sure all the information is there whereas in r/l you can give a relatively simpler verbal instruction.

Even in r/l you can get written instructions, of course. Have you never been sent an e-mail of instructions to get things ready for when he gets home? Never been left a note to find when you arrive at his house?

A lot of it is also personal preference.