Much scarier is dust: at these speeds, even a grain of dust of a tenth of a gram would cause havoc (1.8*10^9 J if I did no mistake in the calculation, i.e. more than the average lightning bolt). Not sure we can pack enough armour on a probe to survive this.
There is also the small problem of dissipating the heat that would inevitably be picked up from the beam. In conclusion, I agree if we want to go there we will have to learn patience, and take a few centuries at least.
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