I have the opposite view on this.
1) Can extend the influence that the BYU football program will have on missionary work, as the local wards and communities will have a spring/summer event and then a fall event (the game).
2) Spring firesides may influence fall game attendance for some who might not have attended otherwise - with plenty of advance notice. We may see more LDS members that aren't BYU-first fans attend BYU away games as BYU fans.
3) Players will be involved. I don't know where the idea that players wouldn't be involved comes from. This gets players a unique and great offseason and travel experience that you can't find anywhere else in college football. Plus, certain players may even get the opportunity to see and tour the away stadium as part of the offseason trip. That couldn't hurt.
4) Being in the offseason, recruits and their families will get to attend. They often cannot attend when the firesides are held on a Friday night during the high school football season.
5) Football team can focus on football during the season. I don't know that the firesides were always a distraction or challenge, but I do know that travel and schedule issues did arise, which absolutely did affect the football team and gameday.