Why not then hourly? If daily is more beneficial than weekly, then certainly hourly would be more beneficial than daily. What about investing every minute, or second?
If you can set up hourly trades, then why not? The likelihood is you are going to get stung for fees by making more frequent smaller trades than by making one larger trade every week. Once you get to hourly trades, you are looking at ~720 trades a month, so unless you are investing huge amounts, you are also going to start getting hit by rounding errors in both the traded amount and the fees paid (neither of which will be in your favor) from your multiple very small trades.
inner-exchange "fee's" are % based not fixed amount.
1x $4k at 0.5% fee = $20
10x $400k at 0.5% fee = $2, $2, $2, $2, $2, $2, $2, $2, $2, $2 = $20
so no extra cost.
the then benefit is that you can be more timely about purchases to get the dips. so you save more then 0.5% by buying at better timings
what does cost though is if your BANK charges per wire transfer. which can hurt if you do daily/weekly deposits instead of monthly.
same goes for btc withdrawals. if your taking out hourly btc instead of weekly, monthly btc that can be 900 blockchain transaction fees instead of just 1 or 4 withdrawals.
so best advice wire transfer into exchange once a month and remove BTC once a week/month.
then during that month, trade as you please hourly or daily.