This is a pretty common question and in my opinion, it's kind of a loaded question. It implies that click-thru rate (CTR) is an important metric to look at when it's not very important.  

I've seen campaigns with a relatively high CTR that ended up not being profitable. I've also seen campaigns with relatively low CTR's that were profitable.

In other words, your CTR has no bearing on your campaign's profitability. In general, you'll see relatively low CTRs with Google Ads because most people do not click on ads.

Regardless, you really want to just focus on conversions, cost per conversion and return on ad spend (ROAS) because in some cases it's more profitable if the CTR is lower. How so?

With Google Ads, since you only pay per click, it behooves you to list the price of your product or service in your Google Ad copy. Why? It's a way of qualifying the visitor.

If a searcher clicks an ad that lists the price, it's a high likelihood they have a budget that matches the price of your product or service. If they didn't have the budget, they probably would be scared off by the price and not click on your ad, thereby saving you money.

This leads to a lower CTR too because you're essentially telling people who can't afford your product or service not to click your ad. Which is what you want in this case. Each click you get is going to be higher quality and more likely to buy whatever it is you're selling, thereby increasing your ROAS.

As you can see, it's not as simple as "Higher CTR is better". You may get cheaper clicks with a high CTR but that doesn't mean you'll generate a lower cost per conversion or higher ROAS.

Does this mean you shouldn't test different ads? Not at all. You want to test different ads to see which will produce more conversions, which may or may not mean it has a higher click thru rate.