Originally Posted by
orbitmic
I’m with the op in thinking that airlines should prioritise serving their customer best interest first and thus adding a link to the eta website rather than a third party.
But arguably, they do exactly that. A picture tells a thousand words - and while this example is for ESTA, ETA and eTA follow similar patterns.
The official site links always come first, only later in a section on "Help with..." is Sherpa promoted.