I'm sorry but what the fuck is with bloodgems and chalice dungeons(new player)

I'm a huge fromsoft fan and have always had a pretty good understanding of build making. but clearly I'm missing something idk anymore. because why the fuck do I need to slave myself away in dungeons that are rng hell to be able to experiment with more weapons and survive in ng+? especially as an offline player I'm forced to do all these chores even moreso.

please tell me I'm overreacting