Compiling source code tends to get messy when you decide to remove it from your system. Also, you'll have to manually update it, any package manager will be unaware of it and can't do anything with it anyway. You'll also be responsible for dealing with conflicts with other software or dependency issues. That's why we have repos. Someone else did all that work already.
I keep my compiler packages in my home folder and them simlinked to .local/bin. This makes it easier to find and remove your manually compiled packages when ur done. If it's a git repo u can just pull and compile the latest tag to update.