Is nanotechnology useful in the medical field?

Might start a debate on this one soon, but I need more insight on this topic.

On the surface level, it does seem like nanotechnology is a breakthrough in the medical fields, but what are the downsides to this?

I think that we tend to not consider the long term effects of technology per se.

Which previously might have been put down to naivety and an overwhelming sense of confidence in our ability to mange technological advancements.

But we should be able to realise by now that technology often incurs hidden costs, which might adversely affect both society and environment.

And notwithstanding the burden of an aged and ever burgeoning population to both society and environment, we still strive to develop ever more complex ways to claw a few more precious months or years from our declining lives.

And as with all technology, nanotechnology will have applications, other than just medical.

And not just in human hands. 

It would also be foolish to think that independent self replicating technology, will always be the stuff of sci-fi.

Why wouldn't the technology increase the health span portion of the length of years, and why does everybody assume that old age is such a burden.

There is adverse affects to everything both saving lives with technology like zed opposes and affects from allowing people to die prematurely because of misguided opinions that we should die younger than neccessary 

Well, I don't see why not. As far as I'm concerned if it can save lives then yeah.