Thank you! I could check that the tag can hide texts from mobile view. However, it couldn't hide the whole table. I tried
<span class="nomobile">
{| class="wikitable mw-collapsible mw-collapsed" style="width: 50%;"
|-
! title
|-
|dfsdf
|-
|}</span>
but it didn't hide the table from mobile. So instead I tried this
{| class="wikitable mw-collapsible mw-collapsed"
|-
!<span class="nomobile">blahblah</span>
|-
|<span class="nomobile">kk</span>
|}
It worked. But isn't there any way to hide the whole table more simply?
Actually I decided to hide it because the table wasn't collapsed in the mobile. So if the question at https://www.mediawiki.org/wiki/Extension_talk:MobileFrontend#mw-collapsible_not_compatible_with_Mobilefrontend.3F_32385 is resolved, then I might not need <span class="nomobile"> in the first place :)