Is it possible to install Ubuntu/Debian on my 16 GB SD Card ? Do I just during installation process chose my SD Card partition and install it (that doesn't work if we have USB) or do I need to install persistance ISO on my SD Card ? The last question how it's with the speed of such demon as this ? I will use that SD Card in laptop slot where I can insert it so I think it should be faster than using USB Adapter.
For what it concerns Ubuntu you can search to follow what in Portable installed system that boots in UEFI as well as BIOS mode.
You can find instructions on how to make an installed system (typically in a USB pendrive) that works with UEFI and BIOS, and is small enough to work in an undersized 8 GB pendrive (7.8 GB). So in a 16 it will be large ;-)
The more general page about how to install Ubuntu in the main site. They keep it updated. There are many blog around in the web that can help you. One that you can find interesting is Installing Ubuntu To USB Drives.
For Debian probably you will chose to install Debian Live with Persistence. If you start from windows you can find useful this post.
An old but always official page about Debian and USB can be this one.
Now some words about speed.
Short version: test it.
Not so short version: test it because each hardware is different.
On one of the laptop that I used there were two USB port. One was a USB 2.0. The second was a USB 1.1. A notable difference.
On more modern laptop you can find USB 2.0 as often as USB 3.0 or 3.1.
To have some hints about speed you can refer to a list of the bit rates of the devices.
It's possible that at the end of all your reading you will decide to test it. Did I said it to you before? :-)