I have been using rclone for over two years now. Typically, I run cron to copy any new files in the directories that are most important to me.
The combination of rclone and B2 storage is quite effective, especially considering its ease of use and cost efficiency.
They didn't even mention the alternative to this statement.
I've only ran applications with environment variables. And since they're allowed everywhere (lambdas, docker images, heroku and whatnot), It's hard to imagine how passing credentials into code, could've been done otherwise.
I know many services that do this. And even if you fight with customer care for RCA they go silent and pass you around to other team members to whom you need to tell the problem again and again.