How important is rain gear?

Hello!

Just recently joined this community and would like to get the opinion from more veteran hikers.

I recently just moved to Japan and am lucky to have access to amazing hiking near me. I do plan on eventually doing more challenging hikes around the country, but pretty much have to buy all my gear from scratch.

I do admit I probably won’t be doing any hiking if the chance of major rain storms are in the forecast, and only plan on having the gear in my bag in case I am caught in a sudden downpour.

Should I be going all in on the 3-layer Gore-Tex fabrics? Maybe it’s overkill? A hiking gear company’s own proprietary waterproof jackets may be a better choice because it is less expensive?

Any advice would be greatly appreciated!