I could have shown you a mass of corrosion from Trojan L16s on the 8 that I threw out. Terminals connections were reduced in weight by at least half, copper wire was eaten to green, heavy gage steel battery box corroded right through.

Whether the self discharge rate matters depends on whether it matters. If I leave the boat in storage for 6 months over the winter (indoors so no solar panel charge) then flooded cells have to be charged. If it doesn't matter to you then it doesn't matter.

My alternator puts out 280 amps at 28V. If I had flooded cells it would boil them to a crisp (or have to be regulated back). The AGMs (440 AH @ 24V) will take this charge and more.

I'm not telling anyone to buy AGMs - just enumerating the advantages. And they ARE advantages - that may or may not be worth the premium price to an individual.