Three experts give their opinion in this article from The Strad magazine and all are in agreement that it is means to an end. Etudes must be practised with technical precision and brilliance as that is what the objective is – a study piece which improves one’s technique. Through these pieces, one develops the skills and confidence to emote necessarily especially during performance pieces with large technical showcase sections i.e. Concertos.
A fourth opinion from my very own beloved mentor and violin teacher Professor Zhao Weijian of the Beijing Central Conservatory (whose view orginates from his mentor in Romania) is that even when practising scales, do so from your heart. The more practise there is to bring in your emotions, understanding phrasing the more creative colorful a musical artist(e) you can be. I cannot agree with him more! So a tip to practise seemingly monotonous pieces is not to do so robotically but whole heartedly!