That's how language works though.
And we use it with a million other words.
The fact that regions have different words für the small version is already showing that Brötchen is the better word, because everyone knows what Brot is because Brot on the other hand is used everywhere, even in Austria and Switzerland.
Dreierbrotchen, Hutzel, Kipfl, Laabla, Laib, Polltaube, Rundstück, Schrippe, Schuster, Weck, Wecke, Wecken, Zeile, Zeilensemmel
vs
Brötchen which means small bread. G_G.
It's super efficient too:
1 Brötchen
5 Brötchen
einmal zwei halbe Hahn.