Schinken… Schinken!

I get what you mean, but no, it would not be secure. The private key in question is really used as a number in a calculation, not as a string of digits. Leading zeroes would just be ignored.

Caution! .ecryptfs is used for an encrypted home directory. I would assume the size is because of Sims 4. Check with mount whether your real home dir is mounted via ecryptfs.

If you want to be sure, delete some big files in your home dir and check if ecryptfs gets smaller. If you delete it, you lose all personal files on that machine.