But besides these advantages, it really has a part in deterioration of our thinking.
Despite these advantages,...But now due to smart t.v we would become more lazy
However, nowadays, due to smart t.v, people are more likely to become more lazy.
Remember, never use "but" to start a sentence in writing.
Another thing, I think you shouldn't use "we" in writing, and I think you shouldn't use "deteriorate" and "deterioration" all time, you can replace by "become worse" or "can't not improve".
For example,
The development is quiet good and necessary but it has an effect which is deteriorating our ability of thinking.
--> The development is quiet good and necessary, but it has several effects which make people's ability of thinking cannot improve.