You first need to understand '말' is not for the meaning of 'word' or 'horse'. In this sentence, '말' is used as a quantity unit which has been used for a long time ago in Korea. One '말' is same as about 18 L. and the mean of '이라도' is similar to your thought; 'even though' ( actually it is a totally new part of word class which is used in Korean but not in English) So, the sentence means directly that 'even though one has three '말'( 54 L) of pearls(beads), they are valued when in chains.'

It's Korean unit of measure ≒18 liters and '서 말' is a lot of that in the sentence

1 말 = 10 되 = 100 홉 = 4.7654 gal = 609.971146 oz = 18.039 liter Korean still use these volume measure units specially in urban. Many Korean are confused by this units. because we used to apply wrong. For example 1 말 of chestnuts = 8kg 1 말 of beans = 8kg (in somewhere it is only 6kg) we are measuring differently. LOL 1 말 of sesames = 4kg Does it make sense? Many people are using this unit as a weight unit. They are saying 10근 = 1 말. This is absolutely wrong. We know about it. but we use it wrong. I use it too. Just because to communicate with them.