The goal of ironing is to put the fabric between an iron and an ironing board, wetting it with steam and heating it with the bottom of the iron. So there are no constraints placed on the fabric:
1) a thermal constrain: if the temperature helps eliminate wrinkles, it needs to be moderate (between 90°C and 140°C). An iron that is too hot (reaching 240°C!) tends to burn the surface of the fabric. Often invisible to the naked eye, this change contributes to premature ageing of the clothing.
2) A mechanical constraint: the weight of the iron and the rubbing caused by the pressing and wear of the fibre lead to a non-elastic deformation (it does not return to its natural state)
These two phenomenon slowly destroy your fabrics and lead to deformations and changes in appearance: loss of elasticity, permanent wrinkles, shininess, felting, etc.
If the goal is the same as ironing: the method is different.
No ironing board, no high temperature, no crushing.
The work is done vertically, the clothing often being placed on a belt or between runners. A gentle tension is applied to the fabric with the free hand and the steam is applied directly to the fabric. The natural beauty of the fibre is restored with the steam and clothing returns to its original appearance... without any stress to its surface.
This simple method is particularly adapted to modern fabrics, often composed of a mix of natural and synthetic fabrics. The synthetic fibres are very sensitive to heat and do not do well with traditional ironing even though they are supposed to be easy to maintain and look nice. The steam iron is a tool that preserves the appearance of the fabrics by maintaining the integrity of synthetic fibres.