Earlier quoted context omitted.
TomTom relies on maps for many of their products. OSM provides maps. Doesn't exactly sound like rocket science to me.
So far as I was aware, TomTom provides a commercial alternative to OSM data. Them helping OSM in that context takes some rocket calculus / is a valid question.
Their main products are centered on fast GPS tracking solutions, which works really well with maps and mapping out maps, but at the end of the day are "just" coordinates. Selling maps in and of themselves is not their core product.