It will help with SEO.
My personal opinion is unless you can keep it updated regularly - don't have one. Having a blog with no recent posts will probably put off actual visitors to your website.
My definition of regular updating would be 2 posts a month. Others will say 1 post per week.
Indeed, Blogging can help to boost SEO quality and also can make a huge difference to your overall website performance in the search engines rankings gaining more customers to your site, if your blog posts are regularly updated and are of high quality, on topics relevant to your audience and highly relevant your customers'questions.
blog is the great way to build a strong presence of a business over the internet. post strong content related to your services and products and try to produce content on fresh ideas and do some email marketing to reach out your audience.
I also think that having a blog is a great option to improve your website SEO. By creating useful and informative blog posts, you can rank for more keywords, build internal links and gain backlinks from other websites. And, respectively, you can increase your web traffic and the time that people spend on your website.