From the picture the link goes to . . . remember that a signal lamp has a reflector that spreads and amplifies the light from the bulb. As the only LEDs on that particular lamp are only pointing "out", it would very possibly render the reflector and its related function inoperative as the light from the bulb would be "out" rather than "everywhere". In other words, probably not a good choice. Especially when compared to the other LEDs for that same bulb replacement that have light sources all around the outside of the bulb housing. To shine one the reflector for best results, in addition to the LEDs that just point "outward".
The other things about using LEDs for signal lights which flash is that you'll need an electronic flasher (to replace the current "thermal load" flasher) and/or an add-in to let the flasher see the same load as it'd see with the former bulbs, so the flasher will work decently well.
Rather than brightness and less electrical system load, the advantage of using LEDs for signal lights is that they illuminate quicker than an incandescent bulb does. That can mean that a following driver can see your brake lights at full illumination about 15'+ sooner with both vehicles travelling 60mph (for example) than with the stock bulbs.
Just some thoughts,
CBODY67