Are the security techniques used to protect a site from being hacked or pirated useful?

100% useful but the issue is that...
with each passing day, newer vulnerabilities are discovered and exploited before being fixed

Both there are multiable security techniques for each issue for example you are using encoding to save your data from be read by unauthorized entity and ssl to be sure that your package reach to certified server, each security issue have its fixes, and it is depends on your requirments