Why is Tactical Voting Important?

-Electoral Reform Society says that 6.5 Million Votes voted Tactically [Held their Nose] -SwapMyVote [Website] allowed for Precise Tactical Voting. They allow 2 Voters in Different Constituencies to make a Vote for one another's Preferred Party -John Curtice [Election Expert] said that Tactical Voting affected 77 Constituencies during 2015 General Election