For me, it's not a must, but I do appreciate it more than I used to.
I spent some effort, time, and money matching attys and cartos to juices I like and voltages I could create before I had VV. Also, I have had a couple of 5.0v resisted PVs for a long time. Along the way, I found some combinations that perform very well for me. So, when I got my first VV device (I started with VV just like you with a nice little inexpensive VV box which I still have and still use occasionally), I found myself setting it to the same voltages I could create before I had VV.
It really grew on me when I bought a VV device that also employs my favorite feature - Juice Feeder. I have two different types of VV feeders, and I've found that I really appreciate them being VV. I still often use an unregulated feeder, and occasionally use one of my unregulated tube mods, but more often than not, one of my VV Feeders is what is in my hand. A good feeder coupled with variable regulated voltage and a high performance atty creates an incredibly consistent vaping experience.