I think I recall things like "貴方" being in the JLPT N1 test, so it does need to be learned somewhere down the line.
But realistically, the vast majority of people quit learning Japanese far before getting to a level where it is needed to read obscure kanji.
If you're a beginner, focus on the most common readings until you get a better understanding for kanji. As you become better at reading, you will naturally learn many readings if you have the vocab because many words share similar pronounciations.
For example, say you can read "見解"(けんかい）and "学年”（がくねん）, then when you come across the word "見学”（けんがく）, it is very easy to learn to read.
I think it's important not to jump in too deep and slowly building up your knowledge. If you plan to work in Japan and are closing in on a more advanced level, you do see words like "貴方" here and there.
It's worth noting that most hiragana words can also be written in kanji, but depending on the obscurity, almost everyone to almost no one may know them.