It's a bit more complicated than that. Heat Pump Dryers are still pretty uncommon in North America and the ones that are available are very expensive. The least expensive ones that don't seem to have a bunch of negative reviews are priced similarly to a top of the line Speed Queen standard electric dryer and go up from there. That alone tends to put them out of reach of households that would benefit the most from them. They also haven't been around long enough to have gained a reputation, either good or bad, for longevity and maintenance costs.

Whether or not a heat pump dryer pays for itself and how quickly depends on the cost of electricity and how often it gets used.

Related example: I like Hybrid Electric vehicles. They're efficient, reliable, & low maintenance. But every time I've bought one I do a cost analysis to make sure it makes sense to buy a hybrid over the standard ICE model. Last time I think I figured we would have to drive it over 25,000 miles/year for it to make financial sense, which we definitely do.

There's certainly good things about buying more efficient appliances. Long term, it is [hopefully] better for the environment. And it's good to financially support companies who build efficient, high quality appliances. But that's a purchase that needs to come with some discretion. Not everyone needs to run out and buy a heat pump dryer right now. That decision should be based primarily on whether they can afford it and whether it will provide them with tangible benefits.