Because who the hell cares who incrementally improved a light bulb once upon a time?
Can't you read? This wasn't some "incremental improvement". Let me quote a bit of that article again for you:
Latimer created a light bulb with a more durable filament made of carbon. He sold the patent to the US Electric Co. in 1881, and a year later patented a process for efficiently manufacturing the carbon filament. He even wrote a book in 1890 on electric lighting, the first of its kind.
Because of Latimer's contributions, incandescent light bulbs became more affordable and practical, MIT says, thus transforming American culture.
There' I've even bolded the most important part for you.
Henry Ford didn't invent the car by the way, from what I understand he invented the production line, but anyway your comparison is ridiculous.
But why should I or anyone be interested in filament guy?
Because of the bit I've quoted, particularly the bolded part.
So yeah, Biden was pandering to the audience he was talking to and to say Latimer invented the lightbulb is a stretch.
But your initial post implies he said it because he's confused, when a 2 minute Google shows pretty clearly what and who he was referring to.
One could argue that saying it to that particular audience was a pretty shrewd thing to do.
So which is it? Is he pandering to a crowd in a politically smart way, or is he a dementia patient? He can't be both.