question/help needed: how does switch stacking works with dual nic servers (esxi)

Hi,

I'm pretty noob with networking as you can imagine when you see the title...

Anyway, I switched jobs and I ended up working in a small company where I have to manage the network (which I didn't have to in my previous job, but i'm ok, i'm gonna learn.)

Now, this company has 2x EMC vdx-6740b switches stacked for redundancy. I think the link to connect them both is called "ISL".

I figured that because I get an entry when I run this command: show fabric isl

The ESXi hosts with dual 10g nics are connected to both switches. Fox .ex one uplink is connected to port 44 on the top switch and the other uplink is connected to port 44 on the bottom switch (active/standby on the vswitch in vCenter)

I understand that the 2 switches forms 1 logical switch. So from the ESXi host POV, the 2x 10gb uplinks are connected to the same switch.

1) I'm trying to get my head around what's the benefit of having 2x stacked switches connected together. If one switch goes down the other one is there to keep the traffic flowing. But isn't that pretty much the same than having 2 separate switches? From the ESXi POV, whether the switches are stacked or not, if one goes down, traffic will flow to the other one (because of dual nics)...

2) They way the uplinks are connected to the stacked switches: same port on both switch. Is this a requirement when stacking switches? or it's just to keep things organized?