Multiple German manufacturers e.g. Bosch, Wilpu only recommend their 24 TPI (or 1mm tooth pitch) only up to 2.2 or 3 mm of metal, leaving their coarser 14 TPI (2mm tooth pitch) for up to 6mm metal. I've cut 6 to 8mm bars (axes for doors and window handles) with a 24 TPI blade and had no issues... the blade didn't seem to lose any sharpness and the cut was a matter of seconds every time I used it. So what am I missing here by not using their recommended/coarser blade?
As far as I recall, the usual recommendation is to have roughly 3 teeth in the material. That gets it cut and moved out quickly, without grabbing excessively. The finer blade does not have room to store 6-8mm worth of shavings (i.e. in the tooth gullets until the blade comes out the far side) so it does not cut as well as is ideal, since it is "packed full" before it can dump chips.