That's a tough one @Jnix284 There are so many good marketing tools in HS and it also depends on the kind of subscription but my vote definitely goes to "Marketing Automation". It's a game-changer for my team.
We were targeting multiple countries in local languages via email campaigns. As localisation is a must when it comes to regional-based marketing in 2022. Therefore, we were finding a way to use one HS account for multiple countries and it was tough when there are different laws and rules when it comes to data privacy and marketing information and multiple teams using the same HS account.
So we used a complex yet easy workflow based on country & region specific and saved 25% of our marketing budget for Q1!