But from my experience this is exactly how people are using touchscreen laptops in meetings.
I don't see the point of adding a sticker to your laptop when it already can be used as a whiteboard with the added benefits of digitalisation (backup, share, undo, search...)
A lot of people actually share this concern and you are right if you're planning on keeping what's written. I personally use it for practicing coding interview questions and brainstorming.
I bought a whiteboard 2 weeks ago for my home "office". Thinking about it, it would have made sense to buy a big sticker instead which I can stick on one of my windows. For sure that would have been much cheaper. Plus, I would not have needed to drill holes in the wall.
I hope by "whiteboard" you meant a 4x8 sheet of melamine bathroom/kitchen tile underlay sheet - and not one of the more expensive kind with the fancy aluminum borders (which, if you wanted to replicate those, you could find the parts in the hardware aisle of the home improvement store)...?
The 4x8 sheets of melamine backer board is cheap, cheap, cheap! Where I currently work, we have 80 linear feet of the stuff on our walls in our dev area (held up with nails and construction adhesive). It isn't fancy, but my employer believes more in results than being "impressive" (plus, we don't get any clients back here anyhow).