No, that's unreadable code and therefore not idiomatic. The typical way to generate large numbers is to use multiplication.
"Hello, World!" translates to ASCII values
< 72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33 >
… which can be thought of as
10 * < 7, 10, 11, 11, 11, 4, 3, 9, 11, 11, 11, 10, 3 >
+ < 2, 1, -2, -2, 1, 4, 2, -3, 1, 4, -2, 0, 3 >
The code should therefore be written that way. The consecutive elevens can lead to a compression optimization.
+++++ +++++ [- >
+++++ ++ >
+++++ +++++ >
+++++ +++++ + >
++++ >
+++ >
+++++ ++++ >
+++++ +++++ + >
+++++ +++++ >
+++ <<<<< <<<<
] Print:
> ++ . "H"
> + . "e"
> -- .. +++ . "llo"
> ++++ . comma
> ++ . space
> --- . "W"
> + . +++ . ----- - . "orl"
> . "d"
> +++ . "!"
For readability, you should also group the increment and decrement operators in fives. I also find your comments unnecessarily verbose.
This solution uses one more memory cell than the original code. It's well worth it for the readability, in my opinion.