Our demos require a lot prep work such as researching the clients' needs to tailor the demo accordingly. So they definitely need to be scheduled in advanced! What we have been shifting towards is creating recorded demos. Explainer videos are a good first step before booking a live demo
Instant demos, if you can do it, would work better in early stage as the product is getting off the ground and as you try to define product-market fit and are trying to collect as much data as possible.
It may get progressively difficult to deliver these instant demos as you scale especially if you consider the fact that not everyone should receive a demo as they may not be a good fit for your product. You may need to screen prospects and discover their true needs so your marketing/sales team is not spinning wheels for nothing and can also tailor better demos.
On-demand pre-recorded demos, self-led demos, free trials and a combination of these can also be used to screen prospects and lead them closer to the purchase decision. These alternatives can be used to collect information for follow-ups and assess good fit to potentially maximize customer retention and life-time value.
Interesting question @krupa_bhagat . I think the question comes down to how you handle a prospect who has come to your web page, with a question in mind. A instant demo that interests a prospect and gives a glimpse of what the product can do, can lead to easy qualification of the prospect. But a more detailed conversation would be needed for the prospect to understand the many benefits the product can provide. I think a mix is important