Doodles_1

If all you're truely worried about is training Slayer quickly, than yes not picking up charms will increase your xp rate per hour big time. You save more time in the long run if you pick up charms, so that you have them if the desire to train Summoning pops back up. But, I fall into the category of "richer players" who have extra money to spend on Summoning. Still, I think it's worth the small bit of time for charms now, rather than "camping" for them later.