Thanks for the rabbit hole. The faq linked golang CGo issue [0] features `mattn/go-sqlite` too. It appears there is a particular impact for repeatedly calling any C that takes longer than ~20µs but that issue doesn't really try to quantify general CGo impact.

In my entirely unscientific go test on 100000 incremented integers, it's look like "some" impact.

    inserts took:     891.307359ms
    count: 100000       6.76659ms   SELECT count(integer) from itable
    lower one: 1111    31.708µs     SELECT lower(integer || integer || integer || integer) from itable
    repeat one: 1111   64.275µs     SELECT repeat(integer, 4) from itable
    lower4:           149.027976ms  SELECT lower(integer || integer || integer || integer) from itable
    repeat4:          507.223713ms  SELECT repeat(integer, 4) from itable
    concat4:          132.156995ms  SELECT integer || integer || integer || integer from itable

It probably doesn't matter a huge amount for the ad hoc `dsq` use, having them available is better than not.

[0]: https://github.com/golang/go/issues/19574