Some people in Discord have being doing math and are arguing that it might be worth it later on if you're running a full set of solar blast squads, not skipping/FFing through the fight, and are at the point where your units are doing incredibly minimal damage, but they're talking about like 100+% SB damage buff teams. (One person said he had his SB firing on every team including Helper team, so that would definitely help boost your DPS.)

Edit: Should probably mention that player was using a Shine Crystal drop + skill activation first team rather than a SB damage squad to get his SB fired and started again during the first fight if that helps anyone plan a team for that sort of stuff.

I'd say unless you're a player with the girls to make those types of teams it's probably not worth using the extra currency.