Depends on what you are concerned about. Petty theft is common. If you leave stuff around it will vanish. Tamarindo and some other towns have some limited drug related crime. What I would buy insurance for is medical evac. You dont really want to end up in a hospital for anything major. Its cheap insurance and covers evac to USA on private aircraft.
Travel insurance is a must on all vacations. I live in Mexico and it’s really common for people to end up making go fund me accounts begging for money as they had an accident and didn’t have insurance.
Car rental insurance is a whole different issue that should not be tagged on this post. People should inform themselves about that in other posts on here.
I get travel insurance for every trip i do both local and international trips. It’s like 65$ or something. And yeah CR is hella safe.