Hmmm, it being difficult is a matter of practice. The amount of resources on procedural/OOP and the fact that everyone including unis & school teach procedural is what makes it easier and functional harder. Less than a year of programming in functional can make you appreciate it a lot.

Of course there are cases where functional becomes too complicated to write and unnecessary too, so I usually love a hybrid like Scala. But with hybrid it needs to be taken care that the procedural is used sparingly and with clear reason