Invest or amortize?

Hi everyone,

I was discussing with a colleague at work about what we usually do with our bonuses. I usually invest it in VT and forget. However, a colleague was mentioning that he is using it to amortize quicker a mortgage. I never really thought about that option and would be curious to hear what you think. I don't know his situation but here is mine: I have a mortgage in another country in EU (1.7% fixed interest rate), the property is rented and giving me already few extras hundred cash monthly.

I don't believe this is interesting in my personal case but I am curious to hear your feedback, thoughts or personal experiences!