I tried one VESA arm a few years ago to replace the obnoxiously large half-moon style stands LG was putting on their displays. I swear the stand took up half the desk for a 34" Ultrawide I had at the time. I liked it so much that I got two more for the other two displays I have.
Long story short, I'll never go back to using a "stand" for a display again. It's not that the VESA arms offer so much in the way of flexibility, because I rarely move the displays anyway. It's the amount of desk space I get back by not using the stands, and the ease with which I can move the VESA arms to precisely where I want the displays when I do decide to move them.
VESA Arms/Mounts vary widely in cost, and while there is good reason, it is my opinion that if you pay more than around $120 for one, you're just wasting money. Yes, some of them look much better than others... but I don't care because the arm is completely hidden behind the display anyway. Yes, some of them feel a bit easier to move around than others... but I suspect most people are like me and don't move the displays much once they find their own display "sweet spot."
In the end, it's just like almost every other piece of tech you might buy... it's a personal choice.