Out of curiosity, why did the developers not use epoch time / UNIX time stamp instead of using formatted date and time in the database?
The answer is “I don’t know”, and I guess the world of PHP was very different when this all started in the early 2000’s.
But I don’t think it is necessarily a bad design decision. It is standardized, all DB timedates are in a standard timezone, and there are libraries in SuiteCRM to handle date times and their translation to users (which may be in diverse timezones).
I think the real problem is that not every code that deals with datetimes is fully aware of these conventions and these libraries, and occasionally a few bugs slip in.