Don’t worry about missing out on anything, Kemper Cabs are basically IRs on steroids. ?
An IR is similar in concept to profiling a speaker and mic only without the amp portion. However, the way a speaker reacts WITH an amp is a two way street due to the impedance curve of the speaker interacting with the amp’s output transformer. A Kemper Studio profile captures all of this whereas an IR only captures the Speaker and Mic without the amp interaction.
What sometimes makes people feel IR are better or more flexible is that some of the IR loaders which are available for use in a DAW or as standalone applications can simulate the effect of not only changing mics and speakers but also moving the mic position. I am not an expert on how this is actually achieved but it appears to be a combination of swapping IRs, and modelling the blend of different IRs to create the impression of actually moving the mic etc.
Cabs are at least as good as IRs (arguably better) but the choice of what works for any one person is just personal taste rather than quality.