The reason I fly to Sepang for the first test of the season, rather than the second test, whether it be at Buriram or Qatar, is because Sepang is where the manufacturers bring all their new parts to test. There is still a month between the test and the start of the season, enough time to make changes and produce the parts that get chosen at Sepang. It is the most interesting test from a technical perspective, but for the same reason, the less meaningful in terms of how the rest of the season plays out.
The final test of the preseason is different. With less than a week before the season opener, the teams have two objectives at the Buriram test. On the first day, to select which aerodynamics package they will start the season with. And on the second day, to get a head start on the opening round. The last day of the preseason test is more FP0 than experimental playground.
