A QR seating chart does not take paper out of your wedding. You still print something and stand it on an easel: a sign, a card, a mirror. What changes is what is on it. A traditional chart prints every guest and every table, which is why it is large, expensive to letter, and finished the moment it leaves the printer. A QR sign prints one code.
That is the entire comparison. A board of 200 names has to be right about 200 things on the day. A code has to be right about one thing, which is where to look. The names live behind it and can be corrected at any hour, including during the reception.
So the question is not whether you want something printed. It is whether you want the names on the paper or behind it.