When you sew HSTs, you are sewing on the bias. If you are really careful not to tug your fabric and your machine feeds the fabric really well, then you can just use an easy angle ruler (which in effect trims one point) or add 7/8" to the finished size and cut 2 squares and use your angler or tiger tape. Also you have to be a perfect presser.
No trimming needed!
Most of us are not that good
, so we add a fudge factor, then trim. I use BlocLoc rulers and find the additional trim step well worth the effort for perfectly matching points.
If you are happy with the way your triangles come out without trimming, then go for it! There are dozens of methods and tools for making HSTs. Experiment a bit and find the one you like best. It's all personal preference.