I think the newer spring clamps work really well with factory-thickness new hoses. I think they are thicker than the older ones used many moons ago. Sometimes aftermarket hoses have thinner walls making the spring clamp a little looser than it was designed to be. And, if the hose gets old and less pliable, if you remove and reset the clamp, it may no longer seal.
It is also important that spring clamps not be spread any wider than necessary to remove 'em. When the clamp is new and the hose is new and factory spec. they are better than a gear type hose clamp because they will exert a more continuous clamping force over time. Gear-type hose clamped fittings typically loosen over time, as the rubber underneath the clamp deforms.
I try to re-use the spring clamps when I can as long as they will seal the fitting properly. Don't forget that the nipple needs to be clean and smooth to get the best seal too. When you don't want to drain the coolant, you can always add a gear clamp without removing the spring clamp by opening and applying the band beside the spring clamp on the nipple or raised part of the hose. Not pretty, but it works.