Is it because said configuration typically consists of free of charge apps that it can be shared across anyone with a computer or is it about source transparency that makes you feel confident about what you are running?
Over the years, such importance lost priority for me when other closed source / paid (even under $50) alternatives are starting to mature and I can spare some money for apps if it increases my productivity.
I remember that when I could switch from Windows to Ubuntu in 2009 because I ended up using exactly the same apps there (except Putty, obviously, which I swapped with Gnome Terminal). I already had an open source desktop with the exception of the OS.
I'm using GIMP because Photoshop would be an overkill for what I do. Libreoffice is more than enough. Sometimes I do something very basic with Inkscape. All my work is basically browsers (open sourced), an editor (emacs), scripting languages (all open sourced). However I must admit that I have a closed source binary blob NVIDIA driver linked to my kernel.
Putty not only exists for Linux, but is sometimes useful :) In particular, I've used it for serial connections.
The point is freedom and privacy, not saving 50 bucks here and there. Which is not available to everyone anyway, think high school kids and developing countries.