Ideally, there should be no harm in pulling in a library for just 1% of its functionally. A combination of careful library design and tooling should take care of dependency bloat ("shaking the tree"). In practice of course, libraries don't always consider this aspect, and the tooling never seems quite up to the task.
Yeah I think it’s also a matter of API design. Like a crate which by necessity has to handle the “general case” to some degree will often have more API complexity than a solution which is tailored to one specific use-case. For instance, you might have to concern yourself with configuration parameters which have zero relevance to your use-case.
