Definitely, such move is beneficial to bitcoin market. As we have fixed supply and year after year, it is being reduced owed to forgotten BTCs or unrecovered ones from wallets, and the demand is continuously increasing, the price will surely be heading in the positive direction.
There are actually lost bitcoins but we never know or are able to identify exact number of lost bitcoins. There are reports with estimation of about 4 million bitcoins lost, but the exact number can be more or less than 4M.
4 millions or any number, lost bitcoins are gift and donation to everyone.
Lost Bitcoin: 3.7 million Bitcoin are probably gone forever. Notice the word "probably".
Lost coins only make everyone else's coins worth slightly more. Think of it as a donation to everyone.