I would say that there are 2 kinds of "work" involved in wedding photography:
1. The physical stuff like scouting out the locations way before the day of the actual wedding, attending wedding rehearsals to understand how the actual ceremony would go like on the day itself, the actual shooting for the wedding ceremony as well as the reception, and the days after spent sorting through the shots and editing them.
This is definitely a lot more physically taxing compared what a recreational photographer (which I'm assuming the author is) is normally used to. I still remember how my legs just gave up after I came home from spending the whole day running around trying to get all the shots while lugging around a couple of kgs of gears.
2. The mental stuff like how stressful it is to know that you only have one chance to get things right on your client's special day, and if let's say you screw up the bride-walking-down-the-aisle shot, you can't just get the couple to rewind the whole ceremony just so you can get the shot right. On top of that, sometimes if you're unlucky enough you may even face lawsuits from dissatisfied couple asking for a refund AND for you to compensate for their wedding costs and pay for a new ceremony so that they can have those "memories" be immortalised in photos. Don't forget that like in all creative professions, you have to deal with clients who insist that you charge too much cause their 16 year old nephew with a DSLR can do the job for free.
So yeah, wedding photography may be for some people but personally I wouldn't want to make a living out of it, probably because I don't think it suits my more laid back personality.