multithreading - What are the disadvantages of sharing a single sqlite connection (or any database connection) with multiple threads? -

I have read many on stackoverflow ... which advises on using a different connection for each thread but its Not to mention that the bad effect of doing this

Besides, why should a new connection be used for each thread, please tell you what are concurrent issues or reads or writes latency / speed issues ? Besides, what does it mean? When someone mentions that this thread is 'safe'?