For things that happen at UI speed it isn't bad. If I wanted to do something a million times a second I'd worry about it.
Some Javascript frameworks, such as Vue, often do something similar in that you can pass either a sync or async callback and it does the right thing for either. In that case you could potentially inspect the function once and call it many times.
Some Javascript frameworks, such as Vue, often do something similar in that you can pass either a sync or async callback and it does the right thing for either. In that case you could potentially inspect the function once and call it many times.