The Talmud relates that they knew a secret ingredient called Maaleh Ashan that could make the smoke from the incense rise straight up in a column.
According to the Mishna (Yoma 3:11), the Rabbis criticized the House of Eutinos (among others) for their refusal to share the knowledge of the Maaleh Ashan.
The Gemorah (Yoma 38a) states that the House Eutinos defended themselves to the sages because they feared that if they revealed the secret, it would be used for idolatry (Yoma 38a); there are differing traditions as to whether the Rabbis accepted this defence and removed the censure from Eutinos.
The replacement workers could not compound the incense in a way that made the smoke from the offering rise in the expected manner.
Commentators connect the use of this phrase in this Talmudic passage to its use in the marriage ceremony to illustrate interpretive ideas—that everyone has unique talents which must be recognized, that it is sage to accept with grace what one cannot change—connecting the stories of the House of Eutinos and House of Garmu with wisdom and insight necessary to maintain a harmonious marriage.