The accusations are a first step, intended to bruise his image so he doesn't get enthusiastic public support for the next thing that happens.
At a minimum, you'd expect this to lead to a drummed-up arrest warrant which will keep him from being able to come back home in the future. That could impact his career in various ways, and it would also keep him at a distance if anything unfortunate were to happen to people he cares about.
This sort of thing happens all over the world to some degree, but Putin has become remarkably bold about it over the past few years. Just outright jailing people and killing them off. There's legitimate reason to be concerned for anyone who speaks out.