A brush tip imported through the brush editor via + Import, at least I guess you mean the brush editor because you did not name from which editor you speak and Krita’s GIH editor can not import the created brush tips if I remember it correctly, is imported into Krita, exists, is there, and nothing changes that if you don’t delete it.
And if you close Krita accidentally after you imported the brush tip via the brush editor, then Krita will ask to save any unsaved open document first, so you can not lose anything if you don’t stupidly deny the saving offer from Krita, but if you do, then your progress up to the last save is gone. But not the imported brush tip.
In my eyes, you can’t create a real GIH brush tip with multiple pictures via the stamp option from the brush editor, simply because it can only take the selected part of your canvas into account, or if nothing is selected, the whole canvas.
To be honest, in principle I know how to create GIH brush tips in Krita and for something simple, quick and dirty Krita is sufficient. But if I want to have options and control over the creation then I use GIMP for creating them! Because I won’t cut of my hand if I don’t have to, and I don’t use a worse tool and dump the options and control I can use if I have the option to use the better tool for the job which clearly is GIMP. And @AhabGreybeard says principally the same with his own words. All that is one reason for me to usually link to the manual chapters of GIMP describing the creation of GIH brush tips. For instance here or here.
And this is, by the way, something you already knew if you had, following the rules of our forum, used the forum search on the topic which brings up a lot of already found solutions and discussed information:
Gimp Image Hose with 22 hits.
GIH Brush with 88 hits.
Animated Brush with 500+ hits.
Hello @AhabGreybeard! 
And now I’m out for some time, my usual care time in the nursing home.
Michelist