Why is it expensive to sell on OpenSea?

Could you please explain why selling on OpenSea is often perceived as costly? Are there any specific fees or charges that contribute to this costliness, and if so, what are they? Additionally, are there any steps or strategies that sellers can adopt to minimize these expenses while still effectively navigating the OpenSea marketplace? Understanding these aspects would greatly assist in evaluating the overall financial viability of selling digital assets on this platform.