There are several answers to this important point. The first is that species are part of ecosystems and that ecosystems provide a wide array of ecosystem services that are valuable in a number of different respects and that can be valued economically. When you do that kind of evaluation, it is often the case that the benefits of conservation or restoration outweigh the costs that are associated with that.
The problem, of course, is in terms of what is internal, what is internalized, to private decision-making. Many of the benefits associated with conservation or restoration are public benefits, ones that are felt and experienced by the nation as a whole and ones that, in many cases, may only be experienced later in time.
The problems are primarily associated with private decision-making that allows the externalization of costs, where economic activities can expose those costs in the form of environmental degradation that requires other people to pay for the damages, and with short-termism, that is, focusing on only what happens over the next few years without sufficient regard to what happens in the more distant future.
Species are crucial components of ecosystems, and ecosystems provide valuable services. The problems are, effectively, undue privatization and insufficient accounting for public benefits and for the long-term benefits.