One symbol that increases CTR by 2 times

One symbol that increased CTR by 2 times. Do you use it in your ad headlines?
While experimenting with Facebook Ads, Outbrain discovered:

1. Headlines using three exclamation marks (!!!) instead of just one received almost twice as many clicks as those with other punctuation marks.

2. An ad with a red flag emoji in the headline had a 2.4 times higher CTR than an ad with no emoji.