Lappland/Chen sp gain

I have noticed that Lappland don’t gain sp per second, instead she must strike opponents, as Chen.
Why did they do this?
Are there others operators with this particularity?
Silvervash gain sp normally.

yes, because their skill sp regen type is per hit (silverash too, on his first skill)

edit:
there’s a list for it too https://gamepress.gg/arknights/sp-charge/attacking-enemy

So it’s skill dependent not the operator itself.
Okay, these skills works well with Chen “scolding” talent. (tested)
Thanks again.