Yes, I would probably say it's more figurative. In this context, it just means that the person doesn't place as much significance on it, and instead passes it by.

It's not an idiom, just a very old fashioned way of expressing it. You wouldn't hear/read it in modern texts.

I agree with Christian and Luke. In case you are interested, the quote is attributed to MIKHAIL SKOBELEFF, a Russian general (1844 - 1882). I do think the phrase "to make little account of" is archaic. Also, the quote has a type - I think it should be "thought and deed", not "though and deed".

I've never heard this phrase before, but in context of the sentence it clearly means that the person does not believe that genealogy is important. "I make little account of genealogical trees" could be similarly expressed as "I do not believe that genealogical trees are very important.