>>1
There is no reason to learn it unless you want to support it.
>>5
The grammar is very simple. It's basic indo european grammar with all useless parts (e.g., grammatical gender) removed and all useful parts made consistently regular (e.g., one declination for all nouns, one conjugation for all verbs).
Some may argue its grammar is still too complicated but it takes about an hour to master it which is negligible anyway compared to the time you'll spend learning vocabulary.
The vocabulary is the biggest hurdle as there is no good way to significantly reduce it compared to natural language, so you'll still spend hundreds of hours studying until you're truly fluent.