Is it worth learning from? Can Korean letters be used to spell Chinese with a little change?

Of course, you can check it on the website. According to relevant departments, both Japanese and Korean have evolved from Chinese. Beginning with Xu Fuyuan's voyage to the Western Ocean in the Qin Dynasty, China ranks second among the four ancient civilizations, and its culture is far longer than that of Korea and Japan. So Chinese characters are the ancestors of writing, even in Europe and America.