Agreed. A cheap 40 watt soldering iron is really meant for touching up plumbing. And a cheap 10 watt one will cool down too quickly.
Electronics are heat sensitive. A reliable solder joint needs to heat quickly, flux stripping off any oxidized layers, everything melted, before the heat goes up the lead and fries the component.
This means you want an iron that is temperature controlled, and heavy enough it has some thermal mass so it doesn't cool quickly.
I've worked with cheap irons after getting used to my $60 temperature controlled iron, and yes you can use them, but it requires more experience, skill and care to do well, which in practice is equivalent to saying less reliable results.
Electronics are heat sensitive. A reliable solder joint needs to heat quickly, flux stripping off any oxidized layers, everything melted, before the heat goes up the lead and fries the component.
This means you want an iron that is temperature controlled, and heavy enough it has some thermal mass so it doesn't cool quickly.
I've worked with cheap irons after getting used to my $60 temperature controlled iron, and yes you can use them, but it requires more experience, skill and care to do well, which in practice is equivalent to saying less reliable results.