It is quite costly to write to the database for each hit, I guess most downvotes is because of this. If you limit writes by keeping them in some memory cache it's doable for slightly higher loads.
People are prematurely optimizing if they fear is "but but but mah datamoose".
Also, it's not prohibitively costly if you do even slight batching of the events, say batch load between every five minutes or an hour.
I'd love to hear somebody with war stories chime in though!
You're missing the point of why "rolling your own shitting [sic] implementation" is worth it: it's not the speed, it's the privacy.