The flasher unit is what makes the turn signals blink. A traditional one will flash very quickly if it does not detect the current of a bulb, telling you that the bulb is dead. This will happen with LED bulbs because they draw so little current compared to incandescent bulbs. An electronic flasher is used with LED bulbs to avoid that phenomenon.
I assume you're referring to
these 18 SMD LED tower bulbs. They should be adequate for turn signal / running light use. I have the 45 SMD tower bulbs in my side brake lights and they work great.