I am talking about a 28 Adams or a 53 Benny, non-racing cruisers, respectively.
On the 28 I swapped all the tired 10mm DB halyards to 8mm spectras and they served me well using Spinlock jammers. They never slipped never chafed. Harder on the hands but one is wearing gloves, anyway. All sheets were 8 or 10mm DB for comfort, the traveller 6mm spectra.
On the 53 Benny all lines are spectra or dynema as there are huuuge forces there. The electric whinches do the rest of the hard work.
It is well known, that DB stretches a bit and that is the reason why it is better for sheets or spinnaker halyards (save a buck or three) while dynema and spectra (the 'cheaper' one) does not (well, it does a tiny bit but admitting that would kill sales to the enthusiasts [$

$] so they do not mention it).
However, this is only important in the case of racing boats or ocean going ones where forces might appear never experienced on yachts sailed on weekends in harbours like PJ, PPB or MB.
Just look at the data sheets in the cattledogs, you'll see the difference.
If one is into the scientific methods, one could look up a halyard or sheet tension calculator on the net and figure out the correct size and exact need of ones yacht as far as the lines to sail size and wind speed are concerned.
One who is helming a trailersailer is going to be totally overwhelmed in 35-45 knot winds, may be much less, and even the best dynema line will not help, so it is a waste of dough. Any 8mm DB will do there as one must reef early. Very early, so the lines never get too much force applied to them.
If the lines are matched to the sail's size and the hull type in force 10 winds with a good margin, one should be pretty safe. Methinks. This is all subjective.

One must be aware of the necessity of calculating all sails and all reefs at different wind speeds separately, according to one's yachts characteristics (how soon one ought to reef) as the wind strengthens.
It is quite different on racers, especially ocean racers and ocean cruisers. They are obliged to use the best materials as the requirements are shifted considerably within minutes out there. Just think of the S-toH races of the last few decades like the infamous 79 Fastnet race or the 98 Hobart. There is no escape from force 12 winds out there.
Always buy the best your boat needs, but do not over-spend on unnecessary things just because the neighbour did buy something you do not need or a stupid advert blurb promising the world.
Be aware of Chineese crap peddled on the net, as some of the stuff is just total utter rubbish! Buy Australian if possible even if it cost more than imported goods.
Especially Chineese garbage peddled on the net by obnoxcious belligerent people. ...with insidious politics. Just think about barley, meat, red wine, coal, iron ore and from today timber.
I hope my missive helps a bit to decide.
Fair winds!
Merrier Christmas Happier New Year

Ps: recommended reading:
Dashew: Practical seamanship
(google it)