The Collider doesn't just speed up the accumulation of xp. It gives you 5x as much xp, which means it costs 5x less to level up. If you have a 500% multiplier, then you are earning 25x more xp, which means it cost 25x less cash to level up.
If I use Lady Justice Statues to level up, it costs me $234,000 to buy 52 of them and level up. Without the Collider (but with my multiplier), it would cost me $1,170,000 per level. Now if I sell back the 52 statues it costs me only $175,500 per level with the Collider activated. A donut would therefore cost me between $58,500 to $91,833 each.
