Quality Score vs Branding

We have several words in our campaigns that receive an enormous amount of impressions and clicks, but rarely convert for us.

Now, instead of simply deleting these types of words, we see it as a great branding since it only costs us $25-$50 a day.

Is this effecting our Quality Score? How so?

And yes, these words are very relevant to our website and yes, we have used word matching already.

Thanks

Your Quality score of the ad will improve based on the following factors.
1.Ad relevance to the keyword. If the keyword is found in the ad, G considers it to be relevant.
2. Historical performance of the kw in G
3. Your CTR.

So if you are getting a decent CTR and ad is relevant, u may probably not worry about it.

Ofcourse as u r ready to spend that money that doesn't convert..