I'd imagine there would be quite a difference between an effect meant to sustain itself for a limited time to achieve X result compared to how Daemons more purposefully search for energy instead of being granted it to manifest. That and another difference might be the complexity of how a spell is weaved compared to a Daemon, thus due to a spell being much less complex, or at least isn't forcibly held together to the same degree, and more easily disrupted a dispel works. As both a Daemon and it's Wargear for example are the same being, composed of the same energy of the Warp, therefore is it not unreasonable to say a spell cast by a Daemon, or a Human, can be thought of as a vastly lower Daemon, or rather a warp-derived construct. As we do know when preforming Battle Magic the Wind seems to gain a mind of it's own and Ulgu was once the name of a Daemon if I recall obscure lore correctly.
Beyond that, found out where I heard the concept of living spells, Age of Sigmar apparently with
Endless Spells. Which likely are unable to be replicated in this modern day and age of the Empire.