1. For WGM: They will be the first in the history of the WGM to ACTUALLY make a true relationship confession on the show. This will give the WGM concept some true credibility for future episode couples and the fantasies they are delivering to the viewers. Because one couple ended up for real...it could have again!!! This will make viewer wonder "Could this new couple end up the same way?"
2. Jonghyun: Since most of his current fame is attributed to him being on the show with Yura, people are accustomed to them being a couple and most of them WANT him to be together with her. So fan backlash should be very small. A true confession from him would be totally within reason plus closing his stint on the show as a strong male could really be a very good thing for his career. Being the 1st couple to actually become a couple from being on the show puts his name in history!!!
2. For Yura: Out of all 3, hers is the most questionable about it being a good thing, (only because she is an idol). In Korean terms she is getting close to real marriage age, (she's 22 now, 23 is the start of encouraged marrying age for girls in Korea). HJH is marrying age now. Both of them have their careers blooming right now and (if we are honest) GsD maybe has 3 more years and that's about it (new younger girls debut if you get my meaning). So getting into a relationship now is not unheard of for her and usually date someone for a while before actually tying the not.