Alfalfa is a great crop. It has deep roots which store carbon in the soil, it is drought tolerant, it’s high yielding and it’s nitrogen fixating meaning it improves the soil quality and does not require nitrogen fertilizer which normally is a huge carbon footprint. Overall fantastic crop if you need fodder for ruminant animals. The big problem is farming it on an absurd scale in the middle of the damn desert. Alfalfa does not require irrigation in regions with ample rainfall.
I have not used either for cars but I have tried both for driving bicycles. The thing with open street map is that they have a lot more of the small streets that bikes can go on but cars can’t. In my experience google maps usually wants me to drive my bike right on some huge multi-lane car road for 3 hours and totally ignores the bike path right next to it. When I went on a 1 month bicycling trip I tried both but found that OSMAnd had vastly better suited roads. Some of the tiniest tiny roads it sent me on were some of the most memorable of the whole journey. Sometimes the path in OSMAnd will just be a dirt path half a meter wide and I love that. I thought many times who on earth even added all these roads! I’m so thankful for every local nerd who added every single dirt road in his neighborhood on there. Simply amazing sometimes. But yeah it doesn’t work at all if you don’t download the map that’s true. Also I really can’t answer for navigating by car.
Alfalfa is drought tolerant compared to other forage legumes like clover. This means that during drought the alfalfa will fare better and also yield better than clover or a grass like Timothy or blue grass. However as you can see pasture is also on that list you linked. Fodder crops are harvested for their entire biomass above ground and the amount of biomass is very large. It’s a very productive crop and makes a lot of fodder and this fodder is mostly water. Therefore it takes a lot of water to grow. The water required is not extreme in any way however and where I live alfalfa is a rainfed crop that only very rarely has any water deficiency symptoms. The extreme amounts of water applied to alfalfa in the south east of the USA is only because of the desert climate there. Growing beans, corn or potatoes there also requires insane amounts of water. If potatoes were chiefly grown in the desert southeast you bet you would see news articles going around about how terrible potatoes are. In the end it’s only a matter of matching the right crop to the right climate. Even the most water hungry crop on earth will not require irrigation in the most rainy place on earth.