Yes, but why not have the option to add a sorely missed feature in this vehicle? May not be up to everyone's skill set, but it's there for those that want to tackle it. Purely informational which is always a welcome thing in this small community. Also you may not use the rear washer regularly to notice. I know I rarely use mine in comparison to the front washer.
There may also be some corner cases where you may not have the washer fluid available once it stops working and will be SOL. Think out in the middle of nowhere on a road trip.
Another fun little tidbit and makes the actual low fluid level sensor better than relying on the rear washer stopping: The way the washer fluid system is built in our vehicles (as well as many other Ford's with rear washers apparently) is it is a single pump that reverses polarity based on which is used. The reason the rear washer may stop flowing first is due to the longer fluid line (as well as having to run all the way up to the roof line) and needing the entire thing to be primed to have a flow. For the washer fluid level sensor, it sits higher up in the bottle and will give a lot more advance warning when it runs low instead of being when the bottle is completely empty where the pump can no longer do its job. At that point you're relying on what little fluid remains in the lines from the pump to the front washer nozzles.
Personally, and why I am posting stuff like this, is I am very much interested in finding ways to add features back in that Ford never bothered to. There's a ton of potential, largely due to being shared with the Focus platform which in some respects (especially overseas) had a lot more going for it. Unfortunately with the community being so small and many owners that are of the older age groups who just treat it as an appliance (no harm in that), that very few people like myself are willing to dive in to this stuff.