What are good reasons to choose TIMESTAMP over DATETIME columns in MySQL?

Question

Disclaimer: This might be a duplicate of datetime vs. timestamp?, but I feel I am not convinced of the answers:

My question is:
What are the good reasons to choose TIMESTAMP over DATETIME columns in MySQL?

I'm pretty sure I don't know everything there is about the differences between those two, so I will try to list the main advantages of DATETIME (DT) compared to TIMESTAMP (TS) to my knowledge:

• DT is human readable (TS is not without using TO_DATE)
• DT has a possble timespan of 8999 Years (1000-01-01 00:00:00 to 9999-12-31 23:59:59)
  (TS only about 68 years, 1970-01-01 to 2038-01-19)
• DT fields seem to perform better (according to this blog post)
• DT can be used for advanced date calculation (SELECT NOW() + INTERVAL 2 DAY)

And vice versa:

• TS only needs 4 bytes (DT uses 8)
• TS are stored as UTC values and changed according to the client's timezone setting
• TS columns can serve as a "log" for monitoring when a row has changes

The only reason I see for using it then would be the row monitoring, but looking at the range of TIMESTAMP, which will end in "only" 28 years*, I would rather go with an insert or update trigger.

So, what am I missing? I still don't see a really good reason for choosing timestamp for any purpose?

_{* I know, this is appears quite long, but back in the 60s some engineers also decided to shave off 2 bytes of the year field, because their computer systems would never run until the year 2000 .....}

Answer 1

DT columns can also serve as a "log" for monitoring when a row changes, I use them and triggers to do that.

I usually use timestamp when working with a lot of PHP stuff as to cut down on too much date parsing. If the need ever arises, I can update my software to use datetime.

Answer 2

Here's a funny aspect of DT which I already used: Using DT - at least in MySQL - you have the option of leaving either the year at "0000", and/or both month and day: "00-00". This comes in handy for storing birthday dates without requiring complete information!

Answer 3

The main question is: what is the purpose of dateime/timestamp field? If it is just a timestamp like in a log file where you only store the actual time the timestam is the better choice. Because it needs only 4 bytes and we are in the scope what the timestamp can cover it. If it is a date like date of birth the datetime is the good choice. We hope we'll have solution before end of timestamp scope. ;) (Sorry for my English).