The operative words in that sentence are "can do", not "is ideal for". The #4 can in fact do everything, and it doesn't take as much skill as you might think.
So often the "operative words" of one considered a 'guru of woodworking' get embedded in the new comer's mind and mixed up into "the #4 is the only plane one will ever need." Then things can become frustrating when they try to join two boards to make a panel. Of course they can put the two boards side by side to offset any out of square areas. If undulations occur there will be gaps.
Of course if you have a shop full of power tools that might take care of the problem... If they can't afford more to get started than a #4, they likely won't have a shop full of power tools either.
It is fine to try to keep one's shop cost to a minimum. There is a point where a person may find it to their advantage to have tools designed to do a particular task more efficiently.
jtk
Last edited by Jim Koepke; 06-21-2016 at 2:23 AM.
Reason: spelling
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)