It is highly unlikely that you can complete any collections without it.
Previous events have needed 2 iron ore to craft 1 fishing bait and you may have to fish 5 times or more just to get one collectible. As you also need mining tools for the last collectible, you need lots of iron plus lots of tools just to have a chance of completing collections.
And when you complete collections there is no guarantee of the grand prizes (usually pets). People have turned in 50 collections before now and got nothing but decorations.
In the last couple of events to get around the random luck of turning in collections, they made separate goals which enabled you to complete the goals and get a pet. But these goals also needed a lot of the rare collectibles and without the shack it is very difficult to complete.
When doing the goals it is advisable not to "give" any of your collectibles until you are absolutely sure that you have enough excess. The beach ball we are collecting today should be ok to give for today's goals but be very careful handing in any you collect from the chocolatier, sheep and orange trees as these are very likely to be very limited.
Edit - sometimes the shack gets sold later in the event for 80 gems but I think the last event, they didn't put it up for sale - it stayed at 160gems