You say “only” but I would consider 1% to be significant when talking about increasing the install footprint of every Python package in every installation environment in the world. There would need to be some significant benefit to justify that.
The venv I have sitting here uses 241MB with 0.002% of that being the .gitignore file it contains. If I was looking for someway to make venvs smaller I would not waste time considering whether that .gitignore file could be stripped out. However if I realised that I could make the whole venv 1% smaller by recursively stripping out hundreds of pointless .gitignore files from every package directory then that would seem like a worthwhile improvement.