Not planning to implement this at this point, sorry. It's an interesting feature, but my slate is so full right now that I won't get to this.

implementation-wise: I'm not sure that wedging this into our current scroll button approach would be sensible, it is better to have a new scroll method "always" (or similar naming) since a similar request has come up for touchpads in the past.

but I do question whether the effort is worth the benefit. Yes, it saves you a button press when you need to scroll but it doesn't come for free on the maintenance side of things. and the cost is an ongoing one since we cannot ever retire this feature once it's merged.

this is also a feature we cannot ever enable by default, so you'll need something providing access to the configuration option. this is easy enough with the xorg.conf approach, but you'll have to convince a few wayland compositors first that they too will expose this in some manner. otherwise it will just end up being an unreachable configuration option in the long run that costs us maintenance effort but is not actually usable by the majority of users.