The button to go to the top is already there on the very bottom of the page. Also an Active Topic button.
I use the Top button when checking Alerts. Otherwise the I just hit the Active Topic button. I like to look at everything and pick what I want to read, rather than clicking on to each Forum that interest me.
Top is not on my phone, but it is on my computer. Too bad for that. If it was there, that would be perfect.
I just want to get to the top of the current thread I happen to be on to see if I have any new Alerts, like you, but without spending the time to go get all the active topics.. Maybe it would be better to ask for an Alerts link at the bottom. Active Topics takes a while to go and get them all and relist. I just want a quick jump to the top.