What is the best option for promoting our business?

Hello, Anatasia;

Unfortunately, it isn't a "one or the other". You actually need both Content and SEO services.

Search Engine Optimization services need value-add content to search and rank.
Your whiteboard animation explainer video is a sample of value-add content.
The more value-add content you produce and put out there (on your website, social media, youtube or video channels, business networking events, etc.) the better your SEO results.

I also recommend videoing your speaking engagements, ebooks, and webinars for additional content and as lead-generation. If you create content that interested individuals need to "opt-in" or submit their contact information to receive, you will be increasing your lead list and contact list. Once you have the interested individuals' contact information, you can follow-up with additional information, newsletters, complimentary consultations, etc.

If you put out important content and you have a high SEO results but don't have a way to collect contact information of the visitors, you are doing a disservice to your business. A significant amount of content that you publish should have a CTA (or Call To Action) - giving the interested individuals an opportunity to leave their contact information in exchange for a white paper, a video, an infographic, an ebook, a cheat sheet or template.

Hope this helps.

Find out where does your audience hang out the most. For instance, a website like Fool.com. It shares lots of valuable data about investments. So, reach out to them, ask analytics data and maybe your audience is out there. Check if the offer banner solutions.

The good places are also Reddit, Quora, find your niche forums, maybe reach out to Youtube influencers.

First, you need a strategy.

Who is your target market? Define your ideal client.
How will you reach them? Where do you reach them?

Then you need to develop a message that will resonate and call them to take an action.

The best only option today is the SEO process. There are no any SEO services anymore or as Anastasia, you call basic services. There is SEO or NO SEO.

Google's updates forced to act on SEO as a more advanced AI tool in digital marketing strategy so we all had to reg rut from more "slaps" from Google algorithm.

Both the options you suggested are very valid and are good for promoting your business. However, one problem exists: you can’t force people to your site or video.
Marketing materials such as brochures, flyers, and posters work well for promoting your business.
At this point, you may be thinking that there’s no need to use physical materials. I mean we live in an online world, right? However, traditional marketing is still very relevant and useful. It is much more memorable than online ads and you can get a lot of pull from them.
Essentially, these materials help expand your audience. Plus they’re immediate.
You can explain the cryptocurrency concepts in these flyers or pamphlets. Hand them out at conventions or seminars related to cryptocurrency. You should also have a good set of business cards so you can make connections and establish your presence.
While SEO is a great idea, it takes time. The same goes for the video. How will you ensure that people watch the video?
My advice would be to try a combination of both in your promotional activities. PrintStop is one such place to go for promotional products. You can find business cards, brochures, pamphlets, and more there. Direct people to your website or the video from these physical promotional materials. That’s just my two cents.