You do have Video. It's just that you are now using the onboard Video connection
I think what you are asking is what is the addon Video card and what does it do
Users purchase addon Video cards to enhance the Video quality and to boost the performance both in the amount of Video memory and refresh rate. The addon Video card program also has many other Optimizations and display options, including (sometimes) TV and wizards and orientation and so on.
Without the addon Video card installed all these enhanced video optimizations (through hardware and software) will not work
What happens is you will be only back to the capabilities of the onboard Video only, generally being adequate for most display viewing and light gaming (note most quality games require higher Video memory at least)
Therefore, you may notice a decrease in the depth of Video and possibly some of your high end Video resource games will not work
Plus, due to the drop in memory (Video memory) You may notice a drop in computer performance slightly, as the onboard Video tries to use system resource (usually) to cater for your general viewing
Otherwise no real issue
Well the photo you have, that top port is not a video port.
Oh I missed that.