Hi jovan,
The topper you are looking at is certainly a high quality material (100% natural Dunlop).
Buying a mattress/topper combination can be a good strategy if you can test the combination in person and make sure that it’s a good match for you in terms of PPP before you buy it.
A topper can also be a good backup plan if you make a mistake and buy a mattress that is too firm and need additional pressure relief or comfort.
If you can’t test the combination before a purchase though then it can involve higher risks and uncertainty because you are buying two products instead of just one and you won’t know how they will interact with you and with each other until you have the chance to sleep on them (see post #2 here)
Phoenix