This have the downsides that they call for probably high priced gear (I utilised a clicker in a person course and I feel it charge at the very least $20, so if a convention wished to use that in an viewers of hundreds, that’s a big upfront expense & my practical experience was that clickers had been unintuitive, did not often perform, and slowed factors down if anything at all a website would only operate if you presume anyone has smartphones.