It's not punishable, but it's often not optimal.
The marksman in the bot lane generally wants a defensive summoner spell because of how important it is for them not to die early on. Heal is good because you are in a duo lane, and you can use it to not only save yourself, but your support. The heal is pretty substantial, and the speed boost can help you get out of range of threats.
That said, if you're really worried about dying (and don't care about your support not-dying), the enemy has Ignite, and/or your support already took Heal, it's totally fine to take Barrier.
Other options are generally not as good simply because you need that consistent defensive option. Cleanse is highly situational, and should only be taken bot lane if you're going against double CC (e.g., Jhin + Lux). Offensive options like Ignite and Exhaust are really risky, since you need to get close to the target without a defensive summoner, but they can pay off if you're very confident. Teleport isn't as useful because you're generally not going to be roaming as an ADC until the mid-late game. You need to stay bot for dragon control. Before 15 min, Teleport would be more insurance for when you die so you won't miss too much CS, but it would be better to not die in the first place.
Heal is the best in almost every situation as a marksman. It's very useful, even if you don't think it is.