The difference is that I can add braces in the middle of multiple lines, just need to get my changes to match up, and then I can tell it to reformat the changed section/the whole file.
For block indenting, I have to select each block I want to operate on before issuing the block indent command.
Braces let me skip the selecting, requiring the same cursor movement but allowing batch insertion of selection begin/end markers, in a sense.
