<span class="graph" aria-label="A graph showing the price of Bitcoin in USD for the past 8 hours" role="img">{11:30}§2b|2i|3t|3c|2o|0i|1n|0{06:30}[35551[34323]</span>
That describes the container, but doesn’t describe the content. A proper label would be something like “A graph showing the price of Bitcoin in USD for the past 8 hours. The price rises from x to y in the first 2 hours, then slowly decreases to z.”
Not an accessibility expert, but that sounds like an analysis of the data, which does not communicate the same as a chart itself. Fine for a blurb to go alongside it though.
But for hard graph data, I would expect "14:00 $123.456; 14:05 $999.999" etc.
No, I think I disagree. If the raw data told the story then there wouldn’t be a need for a chart for sighted users. The chart helps a sighted user get a feeling for the data, and the alt text needs to do the same.
