To some degree, yes. It does provide some assistance, although it is not as impactful as many other factors.
Publishing posts on GBP aids in maintaining reader and potential customer interest in the GBP, which contributes to its ranking signal. However, relying solely on posts will not suffice.
It is essential to ensure that the remaining aspects of the GBP are optimized, including accurate categorization, comprehensive listing of services and products, proper publication and optimization of the GBP site, and optimization of the website itself.