Earlier quoted context omitted.
I'm not asking for reasons. I'm asking: whom are you grateful to?
In your case, just substitute "feeling gratitude for positive things in your life" with "consciously acknowledge positive things in your life".
I just really dislike people framing it as "practicing gratitude". I guess it comes from the childhood feelings of being thankful to one's parents for stuff, which is then generalized to "any feeling that resembles that feeling".
I can accept "consciously acknowledge positive things in your life" and I can see why it would be beneficial to one's mental health. Depression and anxiety are often caused/worsened by focusing on the negative aspects of life.