In Summer this is a very pleasant place to be. Never mind that it is very ‘touristy’. It is very central and it is by the water. As well as craft stalls there are fruit and vegetable stalls selling strawberries and peas. There are also stalls where you can have a very good salmon and potatoes lunch for a (by Finnish standards) good price. There are other good dishes, sometimes including reindeer. Of course a coffee and cake while basking in the sun is pretty good too.
This is a good spot to stop for a sun and fresh air break if you’ve been in museums or galleries for a while. Again in Summer, stroll a short distance up Esplanadi for a free concert.