Back when we released the feature, it was intended for it to be present only on the web app as laptops and PCs have larger screens, which can be easily seen in public.
On the other hand, mobile devices are much smaller, making it more difficult for someone to take a peek at your portfolio when you’re out and about. Additionally, some people use privacy screen protectors, which makes things even more difficult for the curious ones around us 
Lastly, we didn’t observe much demand for the feature to be added on mobile as well back then. Still, we’ll check again and decide whether to allocate resources to implement it - thanks for bumping the thread up 