I'm a sales engineer and demoing is one of the core parts of the job. I think this is applicable if it's an internal demo or a demo to a large audience, i.e a conference where you have a very fixed window of time to present.
I would never recommend doing this in a sales context though, where you're selling to prospects. Mainly because it gives you no flexibility to pivot and adjust the content based on what they're interested in, and also because it gives off the impression you don't have a lot of faith in your product to perform live.
I'd still 100% recommend having pre-recorded backups however. I was once doing a demo to our largest customer in region and the second we joined the call our core product had a SEV0. I was very relieved to have something to show while the engineers fixed the issue.
I would never recommend doing this in a sales context though, where you're selling to prospects. Mainly because it gives you no flexibility to pivot and adjust the content based on what they're interested in, and also because it gives off the impression you don't have a lot of faith in your product to perform live.
I'd still 100% recommend having pre-recorded backups however. I was once doing a demo to our largest customer in region and the second we joined the call our core product had a SEV0. I was very relieved to have something to show while the engineers fixed the issue.