In case I wish to put my store on hold, do I have to delete my account??

You have an option to upload "under construction" image.

No, you do not need to delete your account to put it on hold. You can add an under construction image to your store to show that your store is not available at the moment. You can enable the under-construction in Settings > General Settings in StoreHippo admin panel. 

Please refer the following helpcentertopic for more information:
https://help.storehippo.com/topic/general-settings