'Contact Attempted' shows that the contact part of the entry source has entered the DE. Now if it goes to the next step (which might be a decision split/an email activity/wait time, etc) is not evaluated on 'Contact attempted'.
Let's say you have set Data extension as an entry source and you have 5 new entries in the DE and had 20 already existing contacts. Also, you have set journey should run for new entries only while scheduling your journey. So next time that journey runs, it should show 'Contact attempted' for only 5 contacts and not the other 20 contacts. Hence, looking at the history you would know that those 5 entered the journey or not. This is its significance.
Now to answer the next question, you can check the status of that particular email activity in the history. In the screenshot below, you can see that for a particular contact, the email activity failed and for another contact it was successful.
If you want to see in detail which contact received the email and the reason why the contact didn't receive the email(if it was bounced), you can generate reports using Analytics Builder in SFMC or you can also use queries using data views.
Hope this answers your question.