You will be able to get along of course, but learning idioms will just enrich your language and makes you more expressive.You don't need them for work or daily conversations ,as much as you need them for reading literature and expressing yourself in compositions. It is inevitable that you will come across many of them while learning English,so you don't have to study them as a separate task unless you are personally interested in knowing them or comparing them with idioms in your own mother tongue.

Of course you can. Unless you live in an English speaking country they are not necessary. Idioms vary from country to country as well and change all the time. Very few people go around saying proverbs nowadays.

I think that is more about how you define communication just want to buy something in the shop or such things like that , idioms is not needed. But if you want to live in that country, to talk to people as local person, only idioms is not even enough, a lot of name of people , affair , local things are required too.

Just work on expanding your vocabulary. Studying idioms is a waste of time. If your vocabulary improves, you'll be better-equipped to understand unfamiliar idioms. Plus, non-native speakers usually seem awkward when using such phrases.

I believe idioms,proverbs make languages difficult to learn.