Ideally yes, websites are fine. In practice, some of them give a terrible experience on mobile. I would love to use a website for that but sometimes, I have to admit that on my an android tablet, the experience is much cleaner because of that. I am sure everybody has already tried to click on a tiny text box or button, and do some terrible zoom in/out to interact with some badly written websites... The app is usually optimized in terms of screen resolution and in terms of number of items to display (the website is usually more crowded).

But all in all, I am still much more in love with my N9 and soon my Jolla because the user experience is neat compare to the shitty Android or boring WP8 (I have L920 too)
Having some android apps which would never (or very much later) come on Jolla own plateform is an advantage (how come you can think differently) for a transition period, but given that it works ok!

At the end, obviously, this is not the first thing you have in mind when you decide to buy a Jolla . And apart from games (as pointed by Juiceme), most apps are not that useful because you have already a closed or (usually) better native one.