Tabs make more sense because that’s exactly what they’re for, indents. Ignoring how it looks, which makes more semantic sense for an indent, <indent character> or <space character><space character>? You wouldn’t use a bunch of spaces to indent a paragraph, so why would you use it to indent code?
Generally aligning stuff isn’t nice. But if you do, it’s tabs up to whatever level of indentation you’re at then spaces the rest of the way. So you wouldn’t have to assume a tab size. And the tabs and spaces have different semantic meaning (indent vs alignment) so mixing them makes sense. It’s even built into Jetbrains IDEs, where it’s called “Smart Tabs”.
Although really just adding a level of indent is better than aligning.
No, it doesn’t? Here’s the exact same text content with different tab widths:
The tabs are smaller but the spaces are the same, so the alignment remains.