Perhaps we can all appreciate the idea of “light” being a blessing.  But what about salt.  Of course, salt adds flavour but could Jesus have meant something more?
Well, first of all, salt was something valuable.  It was of such great value in the ancient world that it was sometimes used as currency. That’s where the word “Salary” comes from
So, when Jesus says, “You are the salt of the earth”, he was talking of something of great value.  And I believe that he was saying to the disciples that they were of value too, of value to God.
But Jesus doesn’t say, “You could be the salt of the earth.”  Rather, he says both simply and directly, “You are the salt of the earth. You are the light of the world.”  Through trust in Him we can believe that we all have value to God.  Christ died for us.

Secondly. a small amount of salt can be sufficient.
When we are faced by the problems in our world, we usually feel pretty inadequate.
And perhaps Jesus was aware of this when he said, “You are the salt of the earth”.
What effect could the disciples have in a world where they counted for nothing.  And yet they were able to do something which had a lasting effect as the Church grew and spread.
Jesus uses several metaphors to indicate that size need not be important.
He speaks of how a little yeast can transform flour into bread.
He says that if you have faith as a grain of mustard seed you can do great things.

Finally, yes salt is about adding flavour, making a difference. You don’t have to be to be someone special to add flavour to life.
I remember two sisters from Bradford.  While I was their Minister one was dying of cancer, but she was a joy to visit and her strong faith added flavour to all who went to see her.  Her sister had led a sad life, with a failed marriage.  I was told that she had a beautiful singing voice but had long since given up singing, and was rarely present at Church.  Sadly, she seemed to carry resentment with her.
Jesus says, “If salt has lost its taste, how can it be restored.”  In reality salt cannot lose its taste.  But we can lose our “saltiness”:

By not believing that we have value to God
By thinking we are too small or insignificant to be important
By not adding flavour to the circumstances and relationships we encounter
We are called to have an impact on the world, bringing out the presence of God, but it won’t come from sitting in Church.  We, as followers of Jesus, fulfil our roles as disciples when we flavour the earth and illuminate the world with our actions and words that ultimately point to Christ. I end by quoting part of a hymn not in our book:

“A little bit of salt will quickly show its worth;
A little bit of faithfulness will change the earth.
God, make us worth our salt — a church that’s glad to be
The change that you desire in each community.

It’s tempting to remain well-hidden, quiet, bland —
Yet, God, you make us salt and light to change this land.
You send us out to love, to build and to repair,
Till peace and justice flourish here and everywhere”