I actually don't think either SEI or IEI is more clean or more messy. However, to not get buried in a mess, each type must use its role function. If it gets lost in its leading fct to the negligence of other fcts, it will probably end up becoming especially messy. I don't think the weak Te helps either as I think Te can really help with maintaining things and knowing which things are worth maintaining and in what ways, as well as when to keep or get rid of something. Te can also help track things a bit. So an organizational system via Ti is another thing that will be useful in being tidy.

That said, I do think Si valuers in general may be more likely to hoard. Si/Fe might hoard for sentimental reasons, assigning emotional meaning to all the stuff. Si/Te may hoard because it's very aware of the usefulness of objects and how they might later be of use to it. The underlying theme is potential and possibility.