Very customizable (I like having number row always visible, and having long press for symbols on each letter).
Has gif support built in.
My biggest pain point is:
It auto corrects words that are spelled correctly to other words. I type "our" and it changes to "out", I recently typed "purpose" and it changed it to "purple". Autocorrect is awesome and necessary, but I hate that it corrects words to other words and not just typos. I wish I could find a keyboard that has the things I like without this annoyance.
It has a number of benefits over a normal keyboard:
No need for autocorrect since the buttons are so large that it's hard to accidentally press the wrong one
It's symmetrical so both thumbs can type any letter, so you can type faster, in fact the world record typing speed on a phone was set on a one-handed version of this, i'm sure with the two-handed you can go even faster
Pretty much everything I need can be hit without switching to another layout (no need for a symbols page)
The other features of the keyboard are easily accessible, like, copy/paste/select all/undo/redo etc.
It's awesome, it's foss, and not a keylogger like most keyboards.