No this does not make sense. It has been a while but normally I train a UNITE+INSDC classifier on my laptop (16 GB) without issue. @Shuai_Man there is a lot of advice on the forum for reducing memory demands while training the classifier, this should work in your case as well.
@colinbrislawn released some pre-trained UNITE classifiers a short time ago. I suggest seeing if you can use one of these: