If it's not HTML5, they are required to push out an iPad app because there will be something that doesn't work on Safari. Android / Chromebook apps will never appear or will have to wait for the HTML5 version, and it will never be properly navigable across all devices with bare HTML5 (people keep telling me this, I've yet to see a decent demonstration that doesn't just send you to two different places). Hell, these people still use Quicktime...
Our business banking partner insisted on using IE until this year. When they then realised it was going to die and they had to upgrade for Windows 10? We now HAVE to use Firefox ESR editions with a specific .NET Framework, an ActiveX-like control and exceptions for scripting etc. on their domains (their software tries to auto-add them on install to IE too!). If anything, we've taken two steps back in terms of security there, and still have a browser that is NOT our default browser just for banking.
They all started off saying they'll support HTML5, but some of the HTML5 versions are literally play and stop and that's it. A load of sites break when you try to just play a movie, and how do I stop it auto-playing? Oh, there's a plugin/extension/js for that.
We need to get off our arses and just say "Fuck off. Plain HTML5 and nothing else or we don't visit". I still run across pages that want Java and all kinds of junk.
Relying on a plugin of any kind, even Flash, (plugins have to be native code) is inherently not cross-platform and is a security risk. You have no idea if that plugin's breaking open your SSL sessions and handling other data from sites insecurely.
Trouble is, the places that MATTER (i.e. schools which are teaching the children how to use a computer, and banks which are holding your money to ransom if you're anybody) don't give a shit. We're still fighting banks on "but this is more secure" when they make us run closed code in a closed plugin tied into closed sites on a particular browser that's not your normal browser and is - by definition - outdated. It shouldn't be.
The quicker Chrome blocks all this shit, and Microsoft Edge and Safari follow, the quicker people will have to fix it to make things work as before.
Don't let the banks pull the "You must use IE shit" any more. Literally just switch them off and go "We warned you, now you'll need to follow best practice as we've said for decades".