I've seen people refit Clan 'Mechs with SBGRs, even with access to HAGs, simply due to its ability to project a sheer quantity of LB-X pellets at long range. It fills a niche even Clan stuff can't quite fill.
Yeah, it's a bit of a shame that the Silver Bullet ammo option was scrapped for regular gauss rifles, but then again autocannons get a rough enough time already without a weapon crowding out the only truly good autocannon type (LB-X's).