I would guess that they are as safe as the light fitting you put them in. I trust that is an external fitting. Unsure of the value of colour changing lamps outside the garage though.
It is the water resistance of the light fitting you should be considering. Most bulbs can go anywhere if installed inside the correct housing, which are rated for both ingress of insects/dust, and ingress of water.
If this light is outside, and not protected from rain by a porch over the top, you should be fitting it in a housing that has at least an IP44 rating or higher.
I doubt you will find one, as most are designed for bayonet or screw fitting bulbs, not GU 10.
Yes they can be used outside...but only in an IP rated fitting.These are available in the gu10 format...generally with an IP 65 rating.They will need a hole 65-70mm dia and a 50mm clearance from a combustible surface.Check the depth available behind the fitting...I assume you want to fit them in the soffit?