I've grown to dislike activate, because it breaks the simple rule of "never run pip, python, etc., only run your-venv/bin/pip, python, etc.". Now the rule is "Don't run pip, python, etc., unless you've previously run activate and not deactivate" - and it has the complicated special case of "make sure the command exists in your virtualenv." (For instance, it's definitely possible to have a Python 2 virtualenv where pip exists but not pip3, and now if you run pip3 install from "inside" your virtualenv it's global pip! Or you might have a Python 3.6 virtualenv and type python3.7 and wonder where your packages went, or several other scenarios.)

If you have the shell prompt integration to remind you whether you're in a virtualenv or not, it's fine, but I don't always have it, and I find it helpful to manually type out the full directory name (generally with the help of up-arrow or tab...) so I know exactly what I'm running.