In general, videos are a proven way to market services and products. They present a way to engage the audience, captivate interest and set the ‘tone’ of your service which text and images alone dont provide.
However it also depends on the video content and quality. As a reference, I always like to give commercials as an example. Imagine watching TV and two commercials come on. The first is your standard commercial - video, background music and a voice. The second is just text on the screen. Which is going to grab you the more? It’s always the former with the latter essentially just reading text on the screen for up to 60 seconds.
In a nutshell, I’d always recommend adding a video but don’t just put one up for the sake of it. Take the time to put together a concise, professional presentation - potentially even outsource to a video editor on Fiverr. For a non-visual gig like programming, consider putting up portfolio work in a nice image slider presentation with a voiceover on top concisely explaining the service you provide.