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In beginner-level orchestras, that's mostly what the cello section will see. And cello parts are often not much more interesting than that when playing dance music such as Strauss waltzes.
But most music is not like that at all. By the time you're playing intermediate-level music, most orchestral cello parts are much more interesting; I would guess that they probably get the second-most melody of the string sections after the first violins.
Consider the attached file: it's the cello part from Holst's St. Paul's Suite. Holst wrote the piece for a high school orchestra, so it's intended to be playable by intermediate-level students. Even at that level, it definitely doesn't look like a percussion part.
And here's what a symphonic cello part might look like. This is the cello part from Brahms's 4th Symphony, which is on my orchestra's next concert program when we resume in September. I think it's fairly typical in terms of how much melody, harmony lines, and rhythmic material one would see in a 19th century orchestral cello part.