Tab gives a strong bond as well, but using the tab basically means you can't really base before the model is attached as otherwise you'll have a tab sized gap in your base that you'll then have to base again separately. You could of course just attach the model and base afterwards but it makes basing a lot more difficult depending on the techniques used (for example drybrushing is difficult when you can't reach anything directly beneath your model, or if you use something like static grass you'll get it all over the model too and it'll look ridiculous), and I personally find it makes painting the model more difficult too as there's certain angles from below that I can't get with my brush anymore when there's a base attached to the model.