This is what backups are for
The OP's question was about increasing efficiency by saving about 6 clicks. On my system, I do this:
Open FTP, Connect to server, download fresh copy, open text editor, make changes, <ctrl>-S to save the file, switch to FTP, upload file.
My Mac friends do this:
Open text editor, open remote file, make changes, and press <ctrl>-s to save the file.
That's half as many steps. While a local copy exists in RAM, it disappears when their text editor is closed.
In my experience, people who are interested in reducing 8 steps down to 4 don't do backups. I'm not exaggerating. Maybe that's an unfair or unscientific generalization... but it really is what I've experienced in 25 years of programming.
I'm not making any suggestions to the OP. I'm describing how I've seen "edit with FTP" used and what the dangers are and then he or she can decide for themselves. By understanding the dangers, the OP can choose a model and make sure to arrange for automated daily backups or something.
But laserlight's question is (as usual) more relevant than mine: When you use the "edit with ftp" model, you tend to avoid version control unless you develop a specific plan for it.