It's not really analogous to, say, driving old, restored cars. These browsers are rootkit magnets. The people who use this unmaintained software are inherently less safe.
Although come to think of it, if all the rendering is being done on the server side, and nothing but an image map is being delivered to the older browser it should be perfectly safe for these ancient browsers to navigate to even the most dangerous websites, provided that the server side component doesn't get hacked, because the server side component will be delivering nothing but safe images.
Personally, if I was making a film set in the 1990's I would go for the IBM WebExplorer browser (http://virtuallyfun.superglobalmegacorp.com/wordpress/wp-con...). It has awesome graphics.
This makes everything reproducible for multiple takes, lets your art guys have ultra-fine control over the presentation of everything, and lets the actor focus on acting, not driving a computer.
Alternatively have the keyboard set up as one big "anykey" to advance the animation. The advantage of this being that keyboard strikes would be synced with screen updates, if there is ever a shot where you can see both the fingers and the screen (which is typically avoided, but still).
One thing the software industry has been very good at doing is driving the sales of hardware, by requiring more and more resources --- only to do much of the same things as before, maybe with some improvement in specific areas. Many users have no need for the latest hardware nor software, yet they're constantly encouraged to upgrade for security, "new features" they'll never use, etc. (I'll admit that some of these, like security, could be valid concerns.) Upgrading to newer software with higher resource consumption, they wonder "why is it so slow?", and that eventually leads to perfectly fine hardware going to waste. In particular, the extremely fast upgrade cycles of browsers makes their contribution to this gross waste a bigger part than a lot of other software.
> The people who use this unmaintained software are inherently less safe.
A lot of exploits today won't even run on older systems. Older browsers also having less features is also a reduction in attack area - e.g. if there was something vulnerable in HTML5 video or CSS3 animation, a browser that didn't support those features would be inherently immune.
Never could get it to load.
I don't think that my tablet is a root kit magnet, nor that I'm inherently less safe. I just find that this hardware works well enough for most of my needs, except now for browsing the web, which I never thought would happen...
The general diversity of ways people connect to the internet on all kinds of different hardware is enough of a reason, provided there is someone interested in putting the hack together. And there was such a person, so, yay. There's no Court of Hack Justifications one must appeal to, to do this stuff.