I currently work as a full time freelancer. And I develop various applications within excel. I have created lot of applications for many clients. So I thought to create a Youtube channel showing the past work I did. Then I can upload demonstration videos about applications I have done. Then I get a questions how to name this channel. Can I name it as "Freelance portfolio"? I have seen portfolio websites of graphic designers. But haven't seen Youtube channels? Does freelance portfolio always need to be a website? Thanks in advance.
If you want to place only a portfolio on this channel, it does not matter how you'll name it. Because it will be visited only by those who get direct address from you. Unfortunately, I have to disappoint you: YouTube is the last place where any of your potential customers will search for your portfolio on their own. So just name the channel by your own name: this will be the easiest and most logical option.
But there is good news. You can use your channel to really attract new customers. All you need to do is expand its content.
You have rich experience in creating applications for Excel? Great!
Create a training channel and show how to create simple applications. Those visitors who need really simple applications are still unlikely to become your customers, but they will be interested in the training side of your channel and they will help this channel to become popular. This will help you promote your name as an expert in this field.
As a result, the channel will be visited by those who will be able to become your customer in the future. Some of them will initially hope to solve the problem on their own, but they will understand that it is better to turn to such an expert as you (of course, you need to mention this possibility in each of your videos!)
Someone will immediately look for professionals whose videos on this topic are popular, because it means you know what you're talking about.
In both cases, your channel will really start working for you!
The purpose of any portfolio is to show your previous work. If that is best done via video then that what you should use.
As for Youtube channel.. well, check the Terms of Service. You may be granting YouTube more rights to your work than you should by uploading content there. That would be the number one reason what your suggesting isn't widely used -- copyright protection. Remember, if it's on the internet it will be stolen. If you grant a third party (YouTube) unlimited reuse of your work, they may take advantage of that and devalue it all as a whole. And you may have contracts stating your clients own all the IP, in which case you can't grant YouTube use of it, regardless of the intention.
You're also open to trolls, comments, undesired links, etc. I think you need to examine and think about the YouTube market more. Not necessarily who you would send a link to, but those that would find your channel, and if they were a mind to, create problems.
While using a third party site/service to show off occasional work can be great here or there, I'd hesitate to rely solely on such a service.
Most portfolios are hosted on your own domain allowing some protection of the content, even if minimally. In addition since that only means you're using the content, you aren't granting another party use of the IP.