Yes, a table with a trigger will not perform as well as it would without it. Logic dictates that doing something is more expensive than doing nothing.

Does trigger impact performance?

So the answer is No, not without a heavy cost to implement the logic in application level . As I know, triggers will affect performance in insert, update and delete operations. but doesn't affect read performance.

Are triggers good or bad?

Using triggers is quite valid when their use is justified. For example, they have good value in auditing (keeping history of data) without requiring explicit procedural code with every CRUD command on every table. Triggers give you control just before data is changed and just after the data is changed.