While certain parts of PH may be just about 11m above sea level, it is not the entire PH.
PH is about 7xx acres and certain parts closer to USJ is actually around 30m above sea level.
Depending on which section of PH you choose, to generalize the entire PH at 11m is a bit inaccurate.
Of course higher elevation does offer some protection against floods, it is not the only criteria and some area might have high elevation but it's surrounding could be very low resulting in floods even after a minor storm. E.g. The entrance to Sky Condominium in Puchong is very high but the road before the Shell petrol station near the entrance is low resulting often the roads are partially flooded after a down pour.
Similarly persiaran kewajipan also use to flood after a downpour in the past but since the last big flooding, MBSJ has cleared the clogging and improved the drainage. It hasn't flood since then.
While elevation is important, I don't think it should be the only criteria you should be looking at. A combination of good developer, good local council, good workmanship, good community and good drainage design are all important. Higher elevation also comes with landslide risk, so you need to ensure the drainage is good otherwise it's also a concern as there could be soil movement.
Like my boss use to say, got pros sure got cons...ya
Happy hunting ....ya
My buddy's car got trapped in traffic going back to PH during the major floods 2 yrs ago and was written off as total loss. So even if your hse is on elevated ground, you may be unlucky that the flood happened while you are heading back home.