It will be, although it isn't used as often as its equals in other languages, it is certainly used. It will be used by people who are talking about things that will happen in the future if certain requirements have been met (most of the time with an "als", so if you were just on holiday, you probably wouldn't, but if you were having a conversation on a higher level, you probably would. Hope it is clear now.
The trema being in the middle of three consecutive e's, makes it hard for me to distinguish exactly how this is pronounced as the reader says it so fast it seems to run all together, and I believe the purpose of the trema is to indicate a vowel that is pronounced differently from the one(s) around it?
It's a good mnemonic " ei + land , I think that the word eiland can be formed of the words ijl + land . ijl means "not much" or "thin" eg : On top of the Mount Everest the air is very thin - Op de top van de Mount Everest is de lucht erg ijl , but it is only guessing . :)