People may have their own subjective opinions about what is beneficial or not but in Darwinian terms the bottom line is pragmatic selectability and only proven in practice. If in practice something aids survival then it is beneficial, so it really doesn't matter what we each might think or say, we are only here at all imo because beneficial adaptions happen.
The problem is that so-called beneficial mutations can, by no means, be proven to be beneficial long-term which is a requirement of macro-evolution. They can only be assumed to be so (and that by discrimination) within a short time span. For example: a cat that loses its ability to grow fur by mutation but is deemed by certain humans to be rare and exotic. They are protected, fed and encouraged to breed more of their kind. Is this a beneficial mutation even considering that, if thrown back into the wild they would likely not survive?
The mutation has aided survival, and possibly hindered the survival of regular cats, due to stupid humans (apologies to hairless cat lovers everywhere). If the human was not in the picture, would the hairless cat have become extinct or flourished? The problem is it is not testable.
I don't really know exactly what you mean by adaptability, selective breeding shows that life is very adaptable indeed.
By adaptability I mean that which was programmed into the genome at creation from which various expressions produced species separation. But from your point of view, there is also latent adaptability within existing species. A moth can change wing colour from light to dark and back to light again within a few generations. A bird can lengthen or shorten its beak in response to environmental influences. These are not mutations but adaptations for which that genome already has potential. Mutations, on the other hand, are a one way street (short term).
I can't accept that random mutations must always be harmful, that wouldn't be random for one thing. If only harmful or disadvantageous mutations were selected for then of course a rapid decline would surely follow. But equally if advantageous mutations were positively selected for then the opposite must surely be the case. Natural selection typically selects those best adapted regardless of the supposed genetic entropy of Sanford.
Here is an extremely pivotal point I need you to rethink!
The random part is in the DNA, not in the adjectives that later describe the effect.
If a motor is working very well, random changes will nearly always bring it to a stop. The reason is that the list of possible changes that bring it to a grinding halt greatly outweigh possible improvements simply because it is already working very well. The same principle applies to organisms which, as many have testified, work within much narrower tolerances and often rely on other organisms which also work very well.
The other problem I have is assigning anthropomorphic attributes to a concept (natural selection) in order to conceal its impotence - but that is an issue for another time. (Pathetic Fallacy)
Creationists seem to think that humans were somehow originally DNA perfect and that the only way is down, but hard evidence and genetics rather says otherwise, that life was originally very simply and evolved the great complexity we know today, which is the essence of adaptability if you ask me.
We think that because we have been told it by the only eye witness to it all. Once having accepted it, we find overlooked affirmation all over science that it is not as outlandish as we have been led to believe.
We all have the same evidence. We do not ever, ever, deny evidence. But we also know that what you say about it is not true. Evidence does not speak for itself - someone has to interpret it.
Its not the facts we disagree on; its what is read into them. I suggest to you that we have different ideas about what constitutes hard evidence which leads us in opposite directions. (I am fortunate in having been on both sides of this debate during my lifetime)
Please consider the possibility that what you now view as hard evidence 'speaking' to you is far from scientific. (Yes, I know its a metaphor)
Can we, in spite of our presuppositions, evaluate reality? Or do we need to be told what it is because of them? Or are we simply selecting and stockpiling for ourselves certain desirable conclusions by excluding undesirable possibilities?