This reminds me of the Tabs vs Space discussion, and how once Bill Gates did an AMA on Reddit and his answer was that tabs was better because of consistency.
If spaces are used you never know how many spaces is one logical level. There is no agreement - some people prefer 2 spaces, some 4 and may be somebody uses 8 or 6.
Even worse - I sometimes see when in a single source file some parts use 2 spaces for one logical indent and some - 4 spaces.
They’re consistent between fonts.
That's not really an argument. Every code editor can be configured to interpret the tab key as desired number of spaces.
In the case when you move code around you will anyway go for Tab/Shift+Tab in any editor.