In my opinion most western voice actors can't really convey the expression of anime character the Japanese VAs can bring to life.
This is caused by a lot of factors not inherently about voice acting performance, but the language differences. A lot of high pitched expressions are simply non-existed in most other languages, for example. Even if you imitated the tone completely, the language itself as a lot of people know and speak will make the aptly toned expression sound very very weird or creepy within the utterance of the target language.
So for most people dub is simply not on point, or a lot of the times even jarring to match the visual expression to the voice. Subs perfectly keep that distinction.
Most of the time people in western culture finding youngsters imitate anime stuff weird because of this distinction, not because they simply heated expressions, which the target language already has but in other tones and forms.
As an older fan, because historically, dubs were utter crap. Until about 20 years ago, only kids anime got dubbed and when it was that version would be edited and censored. Some companies would also put out a parallel uncensored release and if one was available, it would be subs only.
Even when you started to get older teen anime dubbed, the voice casting tended to be pretty bad.
Because it doesn't feel like extra work once you've gotten used to it, and it still feels like I'm watching a Japanese anime as intended by the original creators.