I must say I don’t see too much harm in interlinears myself, used as an elementary key to vocabulary. The important thing is to take the words in the order in which they come in the original, and I think interlinears do that don’t they?
This thread however shows how interlinears have the potential to mislead if not accompanied by a knowledge of Latin grammar and syntax: http://discourse.textkit.com/t/modifiers-and-other-things-embedded-in-a-latin-phrase/13933/1 They’re not much use without that. See for example the passages quoted in the Internal rhyme thread. They’re poetic, with poetic word order, but even in prose it’s important to distinguish nominative from accusative, for instance, and interlinears don’t do that do they? (Petrum/Peter amat/loves Paulus/Paul. Who loves who?)
So I don’t recommend them.