Help Newbie Q #1 - SD File Structure

[PKW57]

So I hope I've attached these screen captures correctly . . .

If I take the SD card our of my phone and plug it into the card reader on my laptop, it shows up as a single drive (G and I see the file structure shown in Fig 1.
If I mount the SD card to my laptop through the phone using the USB cable, it shows up as 3 drives (G:, H:, & I as shown in Fig 2. Drive I: contains all the folders shown in Fig 1. G: & H: have a few folders each.

What causes this and is it important to know?

Thanks in advance for any assistance.

 

[ctc]

So I hope I've attached these screen captures correctly . . .

If I take the SD card our of my phone and plug it into the card reader on my laptop, it shows up as a single drive (G and I see the file structure shown in Fig 1.
If I mount the SD card to my laptop through the phone using the USB cable, it shows up as 3 drives (G:, H:, & I as shown in Fig 2. Drive I: contains all the folders shown in Fig 1. G: & H: have a few folders each.

What causes this and is it important to know?

Thanks in advance for any assistance.

When you connect your phone to your laptop you see the internal phone storage ~8GB and the SD card. You also get a virtual verizon drive that has drivers and such on it.