Is initializing for loops using braced initialization in C++11 considered bad form?

The recommended way to initialize variables in C++11 is using braced initialization, but I almost never see this implemented in for loops:

// regular initialization
for(auto i = my_vector.size(); i > 0; --i){
  …
}

// brace-init-list initialization
for(auto i{my_vector.size()}; i > 0; --i){
  …
}

Is this considered bad form or is it not done for historical reasons?