It can only be seen on alt/usd pairs. And that only happened because bitcoin's price increased a lot in the past few weeks. If you compare it to alt/btc pairs, their price is very low compared to its previous months.
What I can call an alt season is alt/btc pairs shooting up. The ultimate goal in trading alts is to accumulate and increase bitcoin portfolio. But I guess this depends on what you've used on buying that alt, if you use stablecoins like usdt then your profit should be usdt too. Same with btc, if you buy an alt worth 0.05btc, it should return greater amount of bitcoin not the equivalent fiat value when you bought it.