Question about ASUS GeForce GT 710 SL 2GD5

I'm not sure I understand the question correctly.
You can connect three monitors, yes.

What exactly you mean by "so that three independent screens can be displayed" is not clear to me.
You simply have an "extended desktop" that spans three screens.
Depending on the settings, you can define whether the three screens should function "individually" or as "one big one".
This means, for example, that a game is displayed on three screens (depending on the game and the performance of the hardware) or only on one screen. I.e. watch TV on the left, game in the middle, website open on the right - or something like that.

Basically nothing new, rather "tried and tested", these possibilities have been around for over 10 years.

Max. connectable monitors: 3 x

Connections
HDMI Type A: 1 x
DVI-D (Dual Link): 1 x
VGA: 1 x