GPS_NAVFILTER: best value for plane or boat?

The parameter GPS_NAVFILTER in the documentations is explained just a little:

I tried a deeper dive and found the following explanations in a russian wiki:

The default for rover, plane and boat is 8 - that means “extremely dynamic 4G-aitcrafts”.

So I’m asking myself, if it would be useful to set that parameter to 6 or 5 e.g. for a boat?
Or to 6 or 7 for a sailplane?

I tested that on desk with a value of 6, and in my opinion the GPS is ready in a shorter time and the position will be hold much better than with a value of 8.

But I don’t know the exact background of that parameter. Will it destroy any necessary functionality if I use 6 or 5?

So could anybody explain the background please.
And if my thinking is correct - what value makes sense for a boat or a sailplane?
Has anybody tested that values?

Thanks in advance