Many ecommerce stores need SEO help to gain more customers. When looking for the right agency or consultant I would recommend finding one that specializes or has a lot of experience with your CMS or shopping cart solution instead of those that offer more generic ecommerce SEO services. That means you should find a Shopify SEO, WooCommerce SEO, etc... that can help your store drive more traffic and sales organically.

Accepting Bitcoin might be part of their strategy, but it will likely only play a small part. A great SEO will focus on your products, product categories, internal linking, inbound links, and talk to you about content marketing programs such as data visualizations, blog posts, and other things you can do to gain media and consumer attention.