I have mostly resorted to using the tiny 4.5cm "glue stick" antennas. I carry my radio everywhere and any longer antenna ends up getting in the way enough to be a problem. The stub antennas supplied by Heltec (and almost everyone else) do surprisingly well for their size. But a whip like the one in your picture will more than double your coverage area. It's always a tradeoff.

Part of my reasoning is that I'm usually working through a repeater. I have one placed at a high point in my neighborhood. I have another that rides on top of my car. If my mobile is within reach of either, I'm reaching out a lot farther than the small antenna could manage by itself.