Not a good deal.
150K Bonvoy points for $1,250 works out to $0.008333/point. Most commentators value Bonvoy points at $0.007 - $0.0075. So not only would you be overpaying by 10-15%, but you would also be taking on the risk of Marriott's annual devaluations of Bonvoy points.
Of course, if you need a small number of points for a specific purpose (travel package, a specific reservation, etc.), it could make very good sense.