IMO it is a mistake to consider the LXX too noteworthy. The NT authors quote from it under the inspiration of the Holy Spirit, however that should not be taken to imply that the LXX translation as a whole is inspired.
Wouldn't it be better to reference the Hebrew original?
Yes, except when dealing with the NT quotations in question. And translators are making a mistake if they use the LXX as aan authoritative basis for translating the old testament even for those passages quoted in the NT
Of course none of this is to say the LXX is not useful as it may shed light on translation issues, as mentioned in other answers.