It indeed depends where and how you want to use your boat. If you only go out in good weather and you are in an area where you seas are not rough then you can do without. However, if you really want to go out, far off shore and that can be in rough seas.........you will love stabilizers and once you have them you will never go back anymore.
We did not have them on our Defever 49, but quickly found out we needed them. Even in the marina or port we were rocking and rolling while all other boats were lying quiet, it was embarrassing.
So I did install the stabilizers afterwards, they are zero speed and we basically have them on 24/7 (they are electric). Now we can go out when we want, can anchor where we want, sleep comfortably and even in a port or a marina we now lie rock steady.
At the moment we are lying on the town quay which is not very well protected. Winds were supposed to be max 5 kts, but at the moment I am reading 20 kts again (long live Greek weather forecasting

), sea is getting rough, but the stabilizers keep us completely steady.
So to answer your question: if you can find a boat that has stabilizers you will love them and if you install them afterwards it will cost a lot of money, but still 100 % worth it.