is it ok to program exclusively like this?

While I'm comfortable using @array and $array[$index], I've also thought about what you say and realized that it seems more homogeneous to me. The only caveats I've found are the functions that work exclusively with arrays or hashes (push, pop, shift, unshift, splice, delete, each, exists, keys, values and maybe some more) and the use of slices, which makes the syntax a bit obscure.

That aside, I find it very natural to work like that.