What use are Canary Island date palms?

Why were Canary Island date palms (Phoenix canariensis) planted at each California mission? (But first, were they?) This palm does not have edible fruit. So why would the padres bring this particular palm to California?

Did someone accidentally take the seeds thinking they were the true date palm seeds (Phoenix dactylifera)?

What use would it have been to the Franciscans in the late 1700's?

Certainly they were good for building materials (thatch, braces, posts), plotting a course to your local mission, making a hat. What else?

While looking for uses of the Canary Island palm, I found this reference from the wikipedia article: La Gomera: the Culture of the Palm. This interesting rough translation perhaps is why:

These date palms are much advantage, because making a cut in the trunk for her exude a type of liquor, used as wine, very nice and good to taste. There are tavernas where it is sold. To take advantage of better put a tube from the cut to the entrance of the container that will fill. The rest is to drink it. (Gaspar Frutuoso, 1590).

Ah ha! Would

Interesting articles

• Palms up! / Only one kind is native to the state, but California is defined by these trees. The article says that the Presidio has some of the oldest in the state. Why is that? Have the oldest at the missions died? probably if planted in late 1700's. So are they talking existing oldest? The California Nursery shipped palms to the Presidio. Are these the oldest palms? Who knows this?
• San Diego claims to have the first planted, now dead.